WO2022067841A1 - 一种安全通信方法、装置及系统 - Google Patents

一种安全通信方法、装置及系统 Download PDF

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Publication number
WO2022067841A1
WO2022067841A1 PCT/CN2020/119774 CN2020119774W WO2022067841A1 WO 2022067841 A1 WO2022067841 A1 WO 2022067841A1 CN 2020119774 W CN2020119774 W CN 2020119774W WO 2022067841 A1 WO2022067841 A1 WO 2022067841A1
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WO
WIPO (PCT)
Prior art keywords
link
terminal device
control plane
security
user plane
Prior art date
Application number
PCT/CN2020/119774
Other languages
English (en)
French (fr)
Inventor
李�赫
吴�荣
Original Assignee
华为技术有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 华为技术有限公司 filed Critical 华为技术有限公司
Priority to EP20955861.8A priority Critical patent/EP4213521A4/en
Priority to PCT/CN2020/119774 priority patent/WO2022067841A1/zh
Priority to CN202080105677.5A priority patent/CN116325845A/zh
Publication of WO2022067841A1 publication Critical patent/WO2022067841A1/zh
Priority to US18/193,007 priority patent/US20230239686A1/en

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W12/00—Security arrangements; Authentication; Protecting privacy or anonymity
    • H04W12/30—Security of mobile devices; Security of mobile applications
    • H04W12/37—Managing security policies for mobile devices or for controlling mobile applications
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W12/00—Security arrangements; Authentication; Protecting privacy or anonymity
    • H04W12/03—Protecting confidentiality, e.g. by encryption
    • H04W12/033—Protecting confidentiality, e.g. by encryption of the user plane, e.g. user's traffic
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W12/00—Security arrangements; Authentication; Protecting privacy or anonymity
    • H04W12/08—Access security
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W12/00—Security arrangements; Authentication; Protecting privacy or anonymity
    • H04W12/03—Protecting confidentiality, e.g. by encryption
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W12/00—Security arrangements; Authentication; Protecting privacy or anonymity
    • H04W12/10—Integrity
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W88/00—Devices specially adapted for wireless communication networks, e.g. terminals, base stations or access point devices
    • H04W88/02—Terminal devices
    • H04W88/04—Terminal devices adapted for relaying to or from another terminal or user
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W92/00—Interfaces specially adapted for wireless communication networks
    • H04W92/16—Interfaces between hierarchically similar devices
    • H04W92/18—Interfaces between hierarchically similar devices between terminal devices

Definitions

  • the present application relates to the field of communication technologies, and in particular, to a secure communication method, device, and system.
  • D2D device-to-device
  • UE user equipment
  • the D2D communication can be used.
  • a relay such as a relay UE
  • the relay can establish a protocol data unit (PDU) session for transmitting the remote device, and the data received from the remote UE will be Data is transmitted to the data network through the PDU session, or data obtained from the data network through the PDU session is sent to the remote UE.
  • PDU protocol data unit
  • the present application provides a method, device and system for secure communication, which are used to realize the coordinated processing of the security protection of user plane data by links at both ends of the relay.
  • a first aspect provides a first secure communication method, the method can be executed by a communication device, the communication device can be a second terminal device or a communication device capable of supporting the functions required by the second terminal device to implement the method, and of course other A communication device, such as a system-on-a-chip.
  • the communication device is taken as the second terminal device as an example.
  • the method includes:
  • the second terminal device receives the first request message about the first terminal device from the relay; the first request message includes the PC5 user plane security policy of the first terminal device and the PC5 user plane security policy of the relay ; Determine the first information according to the PC5 user plane security policy of the second terminal device, the PC5 user plane security policy of the first terminal device, and the PC5 user plane security policy of the relay; Send the relay to the relay First information, the first information is used to indicate the user plane security protection method of the first PC5 link and the user plane security protection method of the second PC5 link; wherein, the user plane security protection of the first PC5 link The method is the same as the user plane security protection method of the second PC5 link;
  • the first PC5 link is the PC5 link between the relay and the first terminal device;
  • the second PC5 link is the link between the relay and the second terminal device PC5 link.
  • each device can either activate the user plane data integrity protection method or not activate the user plane data. Data integrity protection method, so that each device is consistent in the way it is processed.
  • the first information is used to indicate a user plane security protection method of the second PC5 link. Because the embodiment of the present application avoids that the user plane security protection methods of the two links are inconsistent when the security activation occurs in a segment, the first information is used to indicate the user plane security protection method of the second PC5 link. It is understood that the first information is used to indicate the user plane security protection method of the first PC5 link and the user plane security protection method of the second PC5 link, including:
  • the first information is used to indicate that the user plane integrity protection of the first PC5 link and/or the user plane integrity protection of the second PC5 link are both enabled or disabled, and/or, The user plane confidentiality protection of the first PC5 link and/or the user plane confidentiality protection of the second PC5 link are both enabled or disabled.
  • the user plane security protection method of the first PC5 link is the same as the user plane security protection method of the second PC5 link.
  • the method further includes:
  • the PC5 control plane security policy of the second terminal device determines the control plane security algorithm of the second PC5 link;
  • the second terminal device sends the control plane security algorithm of the second PC5 link to the relay, where the control plane security algorithm is used to indicate the control plane security protection method of the second PC5 link and the The control plane security protection method of the first PC5 link, wherein the control plane security protection method of the first PC5 link is the same as the control plane security protection method activated on the second PC5 link.
  • control plane security protection method of the first PC5 link is the same as the control plane security protection method of the second PC5 link, it can be avoided that the security activation occurs in a segment (for example, UE-1).
  • the security endpoint policy of the hop-to-hop (hop-to-hop) security is adopted, and the security of the control plane of the two links is inconsistent.
  • the second request message further includes an indication of a security termination policy, and the indication of the security termination policy is used to indicate that the security termination is located on the relay.
  • the user plane security of the first PC5 link and the user plane security protection method of the second PC5 link are the same.
  • control plane security algorithm is used to instruct the control plane security protection method of the second PC5 link and the control plane security protection method of the first PC5 link, including
  • the control plane security algorithm is used to indicate: the control plane integrity protection of the first PC5 link and the control plane integrity protection of the second PC5 link are both enabled or not enabled, and/or, the Both the control plane confidentiality protection of the first PC5 link and the control plane confidentiality protection of the second PC5 link are enabled or disabled.
  • control plane security protection method of the first PC5 link is the same as the control plane security protection method activated on the second PC5 link, thereby improving the security of the link.
  • the first information is determined according to the PC5 user plane security policy of the second terminal device, the PC5 user plane security policy of the first terminal device, and the PC5 user plane security policy of the relay ,include:
  • the PC5 user plane security policy of the second terminal device the PC5 user plane security policy of the first terminal device, the PC5 user plane security policy of the relay, and the control plane security of the second PC5 link an algorithm to determine the first information;
  • the security level of the user plane security of the second PC5 link is not higher than the security level of the control plane security of the second PC5 link, and the security level of the user plane security of the first PC5 link is not high The security level of the control plane security of the first PC5 link.
  • the current requirement that the security level of the user plane security is not higher than the security level of the control plane security can be satisfied.
  • the user plane security of the second PC5 link is not higher than the control plane security of the second PC5 link, and the security level of the user plane security of the first PC5 link is not high On the control plane security of the first PC5 link, including:
  • control plane confidentiality protection of the third PC5 link When the control plane confidentiality protection of the third PC5 link is enabled, the user plane confidentiality protection of the third PC5 link is enabled or disabled;
  • control plane integrity protection of the third PC5 link When the control plane integrity protection of the third PC5 link is enabled, the user plane integrity protection of the third PC5 link is enabled or disabled;
  • the third PC5 link is the second PC5 link or the first PC5 link.
  • the current requirement that the security level of the user plane security is not higher than the security level of the control plane security can be satisfied.
  • a first secure communication method can be executed by a communication device, the communication device can be a second terminal device or a communication device capable of supporting the functions required by the second terminal device to implement the method, and of course other A communication device, such as a system-on-a-chip.
  • the method includes:
  • the second terminal device receives a direct connection communication request from the first terminal device through at least one relay;
  • the direct connection communication request includes an indication of a security endpoint policy, and the indication of the security endpoint policy is used to indicate that the security endpoint is located in on the relay;
  • the second terminal device receives the PC5 control plane security protection method of the first PC5 link and the PC5 control plane security protection method of the second PC5 link determined by the at least one relay;
  • the second terminal device determines the target relay according to the PC5 control plane security policy of the second terminal device and the PC5 control plane security protection method of the first PC5 link determined by the at least one relay;
  • the second terminal device receives the PC5 user plane security protection method from the first PC5 link determined by the target relay;
  • the second terminal device determines the first information according to the PC5 user plane security protection method of the first PC5 link from the target relay, and the PC user plane security policy of the second terminal device;
  • the second terminal device sends the first information to the relay, where the first information is used to indicate the user plane security of the first PC5 link and the user plane security protection method of the second PC5 link; wherein the The user plane security of the first PC5 link and the user plane security protection method of the second PC5 link are the same;
  • the first PC5 link is the PC5 link between the relay and the first terminal device;
  • the second PC5 link is the link between the relay and the second terminal device PC5 link.
  • the relay can determine whether to activate the second PC5 link and the user plane security protection method of the second PC5 link, so that by executing the method provided by the embodiment of the present application, it is possible to realize the security protection between the devices for the user
  • each device can either activate the user plane security protection method or not activate the user plane data integrity protection method, so that the processing methods of each device are consistent. Reduce the chance of error.
  • the first information is used to indicate the user plane security protection method of the first PC5 link and the user plane security protection method of the second PC5 link, including:
  • the first information is used to indicate: the user plane integrity protection of the first PC5 link and the user plane integrity protection of the second PC5 link are both enabled or disabled, and/or, the first The user plane confidentiality protection of one PC5 link and the user plane confidentiality protection of the second PC5 link are both enabled or disabled.
  • the second terminal device determines the control plane security algorithm of the second PC5 link according to the PC5 user plane security protection method of the first PC5 link determined by the target relay;
  • the second terminal device sends the control plane security algorithm of the second PC5 link to the relay, where the control plane security algorithm of the second PC5 link is used to indicate the control plane security protection method of the second PC5 link and The control plane security protection method of the first PC5 link.
  • the relay can determine whether to activate the second PC5 link and the control plane security protection method of the second PC5 link, so that by executing the method provided by the embodiment of the present application, the control system can be implemented between devices.
  • each device can either activate the user plane data integrity protection method or not activate the user plane data integrity protection method, so that the processing methods of each device are consistent. Reduce the chance of error.
  • control plane security algorithm of the second PC5 link is used to indicate the control plane security protection method of the second PC5 link and the control plane security protection method of the first PC5 link ,include:
  • the control plane security algorithm of the second PC5 link is used to indicate that both the control plane integrity protection of the first PC5 link and the control plane integrity protection of the second PC5 link are enabled or disabled, And/or, both the control plane confidentiality protection of the first PC5 link and the control plane confidentiality protection of the second PC5 link are enabled or disabled.
  • the second terminal device determines, according to the PC5 user plane security protection method of the first PC5 link from the target relay, and the PC user plane security policy of the second terminal device First information, including:
  • the second terminal device is based on the PC5 user plane security policy of the first PC5 link from the target relay, and the PC user plane security policy of the second terminal device, and the control of the second PC5 link a face security algorithm to determine the first information;
  • the security level of the user plane security protection method of the second PC5 link is not higher than the security level of the control plane security protection method of the second PC5 link, and the user plane security protection level of the first PC5 link
  • the security level of the method is not higher than the security level of the control plane security protection method of the first PC5 link.
  • the user plane security protection method of the second PC5 link is not higher than the control plane security protection method of the second PC5 link, and the user plane security protection method of the first PC5 link
  • the security level of the method is not higher than the control plane security protection method of the first PC5 link, including:
  • control plane confidentiality protection of the third PC5 link When the control plane confidentiality protection of the third PC5 link is enabled, the user plane confidentiality protection of the third PC5 link is enabled or disabled;
  • control plane integrity protection of the third PC5 link When the control plane integrity protection of the third PC5 link is enabled, the user plane integrity protection of the third PC5 link is enabled or disabled;
  • the third PC5 link is the second PC5 link or the first PC5 link.
  • a first secure communication method can be executed by a communication device, and the communication device can be a second terminal device or a communication device capable of supporting the functions required by the second terminal device to implement the method, and of course other A communication device, such as a system-on-a-chip.
  • the communication device is taken as the second terminal device as an example.
  • the method includes:
  • the second terminal device receives a direct connection communication request from the first terminal device through at least one relay;
  • the second terminal device determines a target relay from the at least one relay according to the security policy assistance information
  • the second terminal device communicates with the first terminal device through the target relay
  • a relay that can guarantee the establishment of the PC5 link can be selected from multiple relays, so as to facilitate the successful establishment of the PC5 connection.
  • the second terminal device determines the target relay from the at least one relay according to the security policy assistance information, including:
  • the second terminal device selects a target relay including the optional PC5 control plane security policy from the at least one relay.
  • control plane security policy of the target relay since the control plane security policy of the target relay includes the optional PC5 control plane security policy, the establishment of a PC5 connection can be supported.
  • the security policy auxiliary information includes the PC control plane security policy of the at least one relay and the PC5 control plane security policy of the second terminal device;
  • the second terminal device determines the target relay from the at least one relay according to the security policy assistance information, including:
  • a target relay whose PC control plane security policy of the relay does not conflict with the PC5 control plane security policy of the second terminal device is selected.
  • the establishment of the PC5 connection can be supported.
  • the security policy auxiliary information includes the PC control plane security policy of the at least one relay and the PC5 control plane security policy of the second terminal device;
  • the second terminal device determines the target relay from the at least one relay according to the security policy assistance information, including:
  • the second terminal device selects one relay from the at least one relay according to the auxiliary information of the security policy, and the security level of the PC user plane security protection method of the relay is not higher than that of the PC control plane security protection method of the second terminal device.
  • Security level target relay
  • the security level of the security protection method for the PC control plane of the target relay is lower than the security level of the security protection method for the PC user plane of the relay.
  • the security policy auxiliary information is pre-configured by the policy control function network element.
  • the network element with the policy control function can preferentially configure the optional state security policy for the target relay.
  • a first secure communication method can be executed by a communication device, the communication device can be a first relay or a communication device capable of supporting the functions required by the relay to implement the method, and of course other communication devices, such as system-on-a-chip.
  • the communication device is used as a relay as an example. The method includes:
  • the relay sends a first request message about the first terminal device to the second terminal device;
  • the first request message includes the PC5 user plane security policy of the first terminal device and the PC5 user plane security policy of the relay;
  • the relay receives the first information from the second terminal device, the first information is used to indicate the user plane security protection method of the first PC5 link and the user plane security protection method of the second PC5 link; wherein, the first information The user plane security protection method of one PC5 link is the same as the user plane security protection method of the second PC5 link;
  • the relay activates the user plane security protection method of the second PC5 link according to the first information, and activates the user plane security protection method of the first PC5 link;
  • the first PC5 link is the PC5 link between the relay and the first terminal device
  • the second PC5 link is the PC5 link between the relay and the second terminal device road.
  • the user plane security protection method of the first PC5 link is the same as the user plane security protection method of the second PC5 link, it can be avoided that the security activation occurs in a segment (for example, UE-1
  • the security endpoint policy of the hop-to-hop (hop-to-hop) security is adopted, and the security of the user plane of the two links is inconsistent.
  • the coordinated processing of user plane security protection can be implemented among devices. For example, each device can either activate the user plane data integrity protection method or not activate the user plane data. Data integrity protection method, so that the processing methods of each device are consistent and the probability of errors is reduced.
  • the method also includes:
  • the relay sends the control plane security policy of the first terminal device and the control plane security policy of the relay to the second terminal device, and the control plane security policy of the first terminal device and the control plane security of the relay
  • the policy is used to determine the control plane security algorithm of the second PC5 link
  • the relay receives the control plane security algorithm of the second PC5 link from the second terminal device, and the control plane security algorithm is used to indicate the control plane security of the second PC5 link and the first PC5 link control plane security;
  • the relay activates the control plane security of the second PC5 link and the control plane security of the first PC5 link according to the control plane security algorithm of the second PC5 link, wherein the first PC5 chain
  • the control plane security of the link is the same as the control plane security activated on the second PC5 link.
  • each device can either activate the integrity protection method for the data of the control plane, Either do not activate the integrity protection method of the control plane data, so that the processing methods of each device are consistent and the probability of errors is reduced.
  • the security level of the PC5 control plane security protection method of the relay is not higher than the security level of the PC5 user plane security protection method of the second link.
  • the security level of the user plane security protection method of the first PC5 link is not higher than the security level of the control plane security protection method of the first PC5 link; the second PC5 link The security level of the user plane security protection method is not higher than the security level of the control plane security protection method of the second PC5 link.
  • a first secure communication method can be executed by a communication device, the communication device can be a first relay or a communication device capable of supporting the functions required by the relay to implement the method, and of course other communication devices, such as system-on-a-chip.
  • the communication device is used as a relay as an example. The method includes:
  • the relay sends a direct connection communication request from the first terminal device to the second terminal device;
  • the direct connection communication request includes an indication of a security endpoint policy, and the indication of the security endpoint policy is used to indicate that the security endpoint is located in the relay superior;
  • the relay determines the PC5 user plane security protection method of the first PC5 link according to the PC5 user plane security policy of the relay and the PC user plane security policy of the first terminal device;
  • the relay receives first information from the second terminal device, where the first information is used to indicate the user plane security protection method of the first PC5 link and the user plane security protection method of the second PC5 link;
  • the relay activates the user plane security protection method of the second PC5 link according to the first information, and activates the user plane security protection method of the first PC5 link; the user plane security protection of the second PC5 link The method is the same as the user plane security protection method of the first PC5 link;
  • the first PC5 link is the PC5 link between the relay and the first terminal device;
  • the second PC5 link is the link between the relay and the second terminal device PC5 link.
  • the relay can determine whether to activate the second PC5 link and the user plane security protection method of the second PC5 link, so that by executing the method provided by the embodiment of the present application, it is possible to realize the security protection between the devices for the user
  • each device can either activate the user plane security protection method or not activate the user plane data integrity protection method, so that the processing methods of each device are consistent. Reduce the chance of error.
  • the first information is used to indicate the user plane security protection method of the first PC5 link and the user plane security protection method of the second PC5 link, including:
  • the first information is used to indicate: the user plane integrity protection of the first PC5 link and the user plane integrity protection of the second PC5 link are both enabled or disabled, and/or, the first The user plane confidentiality protection of one PC5 link and the user plane confidentiality protection of the second PC5 link are both enabled or disabled.
  • the relay receives a second request message from the first terminal device, where the second request message includes the PC5 control plane security policy of the first terminal device and the information of the relay. PC5 control plane security policy.
  • the relay determines the PC5 control plane security of the first PC5 link according to the PC5 control plane security policy of the relay and the PC5 control plane security policy of the first terminal device A protection method and a PC5 control plane security protection method of the second PC5 link;
  • the relay sends the PC5 control plane security protection method of the first PC5 link and the PC5 control plane security protection method of the second PC5 link to the second terminal device;
  • the relay receives the control plane security algorithm of the second PC5 link from the second terminal device, and the control plane security algorithm is used to indicate the control plane security of the second PC5 link and the second PC5 link.
  • the control plane security of a PC5 link, the control plane security algorithm is determined according to the PC5 control plane security protection method of the first PC5 link and the PC5 control plane security protection method of the second PC5 link;
  • the relay activates the control plane security of the second PC5 link and the control plane security of the first PC5 link according to the control plane security algorithm of the second PC5 link.
  • control plane security algorithm is used to instruct the control plane security protection method of the second PC5 link and the control plane security protection method of the first PC5 link, including:
  • the control plane security algorithm is used to indicate: the control plane integrity protection of the first PC5 link and the control plane integrity protection of the second PC5 link are both enabled or not enabled, and/or, the Both the control plane confidentiality protection of the first PC5 link and the control plane confidentiality protection of the second PC5 link are enabled or disabled.
  • the security level of the user plane security protection method of the second PC5 link is not higher than the security level of the control plane security protection method of the second PC5 link, and the first PC5 link The security level of the user plane security protection method of the link is not higher than the security level of the control plane security protection method of the first PC5 link.
  • the present application provides a communication device.
  • the device has the functions of implementing the embodiments of the first to third aspects described above. This function can be implemented by hardware or by executing corresponding software by hardware.
  • the hardware or software includes one or more modules corresponding to the above functions.
  • the apparatus includes: a transceiver unit, and optionally, a processing unit.
  • the processing unit may be, for example, a processor
  • the receiving unit may be, for example, a receiver
  • the transmitting unit may be, for example, a transmitter
  • the receiver and transmitter include radio frequency circuits.
  • the apparatus further includes a storage unit, which may be, for example, a memory.
  • the storage unit stores computer-executable instructions
  • the processing unit is connected to the storage unit, and the processing unit executes the computer-executable instructions stored in the storage unit, so that the apparatus executes the first aspect to the first aspect above. any one of the three methods.
  • the device is a chip.
  • the chip includes: a receiving unit, a sending unit, and optionally, a processing unit.
  • the processing unit may be, for example, a processing circuit
  • the receiving unit may be, for example, an input interface, a pin or a circuit, or the like
  • the sending unit may be, for example, an output interface, a pin, or a circuit, or the like.
  • the processing unit can execute the computer-executed instructions stored in the storage unit, so that the sending method of any one of the above-mentioned first aspect to the third aspect is performed.
  • the storage unit is a storage unit in the chip, such as a register, a cache, etc.
  • the storage unit may also be a storage unit in the terminal located outside the chip, such as a read-only memory (read only memory).
  • -only memory read only memory
  • ROM read only memory
  • RAM random access memory
  • processors mentioned in any of the above may be a general-purpose central processing unit (Central Processing Unit, CPU), a microprocessor, an application-specific integrated circuit (ASIC), or one or more An integrated circuit for controlling program execution of the methods of the first to third aspects above.
  • CPU Central Processing Unit
  • ASIC application-specific integrated circuit
  • the present application provides a communication device.
  • the device has the function of implementing each embodiment of the fourth aspect or the fifth aspect. This function can be implemented by hardware or by executing corresponding software by hardware.
  • the hardware or software includes one or more modules corresponding to the above functions.
  • the apparatus includes: a transceiver unit, and optionally, a processing unit.
  • the processing unit may be, for example, a processor
  • the receiving unit may be, for example, a receiver
  • the transmitting unit may be, for example, a transmitter
  • the receiver and transmitter include radio frequency circuits.
  • the apparatus further includes a storage unit, which may be, for example, a memory.
  • the storage unit stores computer-executable instructions
  • the processing unit is connected to the storage unit, and the processing unit executes the computer-executable instructions stored in the storage unit, so as to enable the access and mobility management function network
  • the element performs the method of any one of the fourth aspect or the fifth aspect above.
  • the device is a chip.
  • the chip includes: a receiving unit, a sending unit, and optionally, a processing unit.
  • the processing unit may be, for example, a processing circuit
  • the receiving unit may be, for example, an input interface, a pin or a circuit, or the like
  • the sending unit may be, for example, an output interface, a pin, or a circuit, or the like.
  • the processing unit can execute the computer-executed instructions stored in the storage unit, so that the sending method of any one of the fourth aspect or the fifth aspect is executed.
  • the storage unit is a storage unit in the chip, such as a register, a cache, etc.
  • the storage unit may also be a storage unit in the terminal located outside the chip, such as a read-only memory (read only memory).
  • -only memory read only memory
  • ROM read only memory
  • RAM random access memory
  • processors mentioned in any of the above may be a general-purpose central processing unit (Central Processing Unit, CPU), a microprocessor, an application-specific integrated circuit (ASIC), or one or more An integrated circuit for controlling program execution of the method of the fourth aspect or the fifth aspect.
  • CPU Central Processing Unit
  • ASIC application-specific integrated circuit
  • an embodiment of the present application provides a chip system, where the chip system includes a processor, and may further include a memory, for implementing the first communication in any design example of the first aspect, the second aspect, or the third aspect. method performed by the device.
  • the chip system can be composed of chips, and can also include chips and other discrete devices.
  • an embodiment of the present application provides a chip system, where the chip system includes a processor and may further include a memory, for implementing the method executed by the second communication apparatus in any design example of the fourth aspect or the fifth aspect .
  • the chip system can be composed of chips, and can also include chips and other discrete devices.
  • the present application provides a communication system, including the communication device in any of the design examples of the sixth aspect and the communication device in any of the design examples of the seventh aspect.
  • the communication system further includes a network data analysis function (network data analytics function, NWDAF) network element.
  • NWDAF network data analytics function
  • the embodiments of the present application further provide a computer-readable storage medium, where a computer program or instruction is stored in the storage medium, and when the computer program or instruction is executed, the first aspect, the second aspect or the first aspect can be implemented.
  • the method in any of the three aspects of the design example.
  • the embodiments of the present application further provide a computer-readable storage medium, in which a computer program or instruction is stored, and when the computer program or instruction is executed, any one of the fourth aspect or the fifth aspect can be implemented.
  • a computer-readable storage medium in which a computer program or instruction is stored, and when the computer program or instruction is executed, any one of the fourth aspect or the fifth aspect can be implemented.
  • the embodiments of the present application further provide a computer program product, including instructions, which, when run on a computer, cause the computer to execute any one of the above-mentioned design examples of the first aspect, the second aspect, or the third aspect A method performed by a first communication device in .
  • the embodiments of the present application further provide a computer program product, including instructions, which, when executed on a computer, cause the computer to execute the second communication in any one of the design examples of the fourth aspect or the fifth aspect. method performed by the device.
  • FIG. 1A and FIG. 1B are architectural diagrams of a system provided by an embodiment of the present application.
  • FIGS. 2A and 2B are schematic diagrams of communication scenarios provided by an embodiment of the present application.
  • FIG. 3 is a schematic diagram of a method for obtaining a security policy according to an embodiment of the present application.
  • FIG. 4 is a schematic diagram of a secure communication method provided by an embodiment of the present application.
  • FIG. 5 is a schematic diagram of another secure communication method provided by an embodiment of the present application.
  • FIG. 6 is a schematic diagram of another secure communication method provided by an embodiment of the present application.
  • FIG. 7 to 8 are schematic structural diagrams of a communication device according to an embodiment of the present application.
  • the PC5 connection in the embodiment of the present application refers to the communication connection between terminal devices based on the PC5 interface.
  • the PC5 connection establishment process in the embodiment of the present application is used to establish a communication connection between at least two terminal devices supporting the PC5 interface. Wherein, after the establishment of the PC5 connection is completed, at least two terminal devices can use the PC5 connection to perform control plane signaling negotiation and/or user plane data transfer.
  • the PC5 connection establishment procedure in the embodiment of the present application may include a PC5 unicast connection establishment (one-to-one communication) procedure and a PC5 multicast connection establishment (one-to-many communication) procedure.
  • the PC5 unicast connection establishment process is used to establish a communication connection between two terminal devices supporting the PC5 interface
  • the PC5 multicast connection establishment process is used to establish a communication connection between more than two terminal devices supporting the PC5 interface.
  • the following embodiments of the present application are illustratively described by taking the establishment of a communication connection between two terminal devices as an example, that is, the following embodiments of the present application are all illustratively described by taking a PC5 unicast connection establishment process as an example.
  • the method of establishing a communication connection between any two terminal devices in the PC5 multicast connection establishment process can refer to the process of establishing a communication connection between two terminal devices in the PC5 unicast connection establishment process.
  • a security policy is a policy used to describe whether to enable security protection, and can be used to determine a security protection method.
  • the security policies used in different scenarios in the embodiments of the present application include at least one of a PC5 user plane security policy and a PC5 control plane security policy, wherein the PC5 user plane security policy includes a user plane confidentiality protection policy in a PC5 connection and a PC5 At least one of the user plane integrity protection strategies in the connection; the PC5 control plane security strategy includes at least one of the control plane confidentiality protection strategy in the PC5 connection and the control plane integrity protection strategy in the PC5 connection; that is Say, a security policy includes at least one of the following:
  • the confidentiality protection of the control plane is to protect the confidentiality of the signaling during the transmission process;
  • the integrity protection of the control plane is to protect the integrity of the signaling during the transmission process;
  • the confidentiality protection of the user plane is to protect the data of the user plane during the transmission process.
  • User plane integrity protection is to protect the integrity of user plane data during transmission.
  • integrity means that the acquired signaling or data is consistent with the original signaling or data and has not been modified. Therefore, integrity protection is to prevent an attacker from "attacking”. Confidentiality means that the real content cannot be seen directly, so confidentiality protection is to make the attacker "unreadable”.
  • the confidentiality protection in the embodiments of the present application may also be referred to as encryption protection, which is uniformly described here, and will not be repeated below.
  • control plane confidentiality protection policy in the PC5 connection and the control plane integrity protection policy in the PC5 connection belong to the PC5 control plane security policy in the PC5 connection; the user plane confidentiality protection policy in the PC5 connection is the same as the PC5 connection.
  • the user plane integrity protection policy in the connection belongs to the PC5 user plane security policy in the PC5 connection, which is uniformly described here, and will not be repeated below.
  • the security policy is divided into three types: REQUIRED, NOT NEEDED, and PREFERRED.
  • REQUIRED is translated as security needs to be enabled
  • NOT NEEDED is translated as security is not required to be enabled
  • PREFERRED is translated as preference enabled or optional enabled, that is, security can be enabled but not enabled. It is explained here uniformly and will not be repeated below. .
  • control plane confidentiality protection policy in the PC5 connection includes: control plane confidentiality protection enabled (REQUIRED) in the PC5 connection, control in the PC5 connection The plane confidentiality protection is not enabled (NOT NEEDED), or the control plane confidentiality protection in the PC5 connection is optional (PREFERRED).
  • control plane confidentiality protection policies in PC5 connections, user plane confidentiality protection policies in PC5 connections, or user plane integrity protection policies in PC5 connections can refer to Examples of control plane confidentiality protection policies in PC5 connections, It is not repeated here.
  • the security policy when the security policy is sent, generally only one of the three policies (REQUIRED, NOT NEEDED, and PREFERRED) is selected for sending. In some special scenarios, it may be At least 2 sends are selected and one of them is PREFERRED. For example, when sending NOT NEEDED and PREFERRED, it means that the security protection is not turned on; when sending REQUIRED and PREFERRED, it means that the security protection is turned on.
  • control plane confidentiality protection policy in the PC5 connection the control plane integrity protection policy in the PC5 connection, and the user plane confidentiality protection policy in the PC5 connection; or, in the PC5 connection
  • the multiple protection policies in the user plane integrity protection policy may be the same, which is not specifically limited in this embodiment of the present application.
  • one or more user plane integrity protection algorithms supported in the PC5 connection are supported in the PC5 connection.
  • the control plane confidentiality protection algorithm refers to a confidentiality protection algorithm used to protect the control plane.
  • the control plane integrity protection algorithm refers to an integrity protection algorithm used to protect the control plane.
  • the user plane confidentiality protection algorithm refers to a confidentiality protection algorithm used to protect the user plane.
  • the user plane integrity protection algorithm refers to a user plane protection algorithm used to protect the control plane.
  • one or more control plane confidentiality protection algorithms supported in the PC5 connection may be the same or have a common item, which is not specifically limited in this embodiment of the present application.
  • the security algorithm may include a user plane security algorithm (that is, a security algorithm used in the user plane) and a signaling plane security algorithm (that is, a security algorithm used in the signaling plane).
  • the security algorithm used on the user plane is used to protect the data on the user plane, and may include a user plane encryption algorithm and a user plane integrity algorithm.
  • the security algorithm used in the signaling plane is used to protect signaling, and may include signaling plane encryption algorithms and signaling plane integrity algorithms.
  • Security keys which may include user plane security keys and signaling plane security keys.
  • the user plane security key is used to protect user plane data, and may include a user plane encryption key and a user plane integrity protection key.
  • the signaling plane security key is used to protect signaling. For example, it can be a key to protect radio resource control (RRC) signaling, that is, an RRC key.
  • RRC radio resource control
  • the RRC key can include an RRC encryption key and RRC integrity. Protect keys.
  • Activating the user plane/signaling plane security means that when the user plane/signaling plane security protection method is determined, you can start to use the user plane/signaling plane security algorithm and the user plane/signaling plane security encryption method.
  • the user plane/signaling plane security can be activated using the user plane/signaling plane security method, the user plane/signaling plane security algorithm, and the user plane/signaling plane security key. face data/signaling for security protection.
  • the user plane security protection method is determined to enable user plane confidentiality protection + disable user plane integrity protection
  • the user plane encryption algorithm is encryption algorithm A
  • the user plane encryption key is key K
  • the user plane data is protected by the encryption algorithm A and the key K to protect the confidentiality of the user plane.
  • the effect of activating the user plane security protection method is that the node executing the activation user plane security can start to perform security protection for the user plane data and start to de-security protection for the user plane data.
  • the two actions of safeguarding and reconciling safeguarding may be further activated separately. For example, after the base station sends the security activation message, the base station activates the de-security protection; after the base station receives the security activation confirmation message, the base station activates the security protection.
  • the security protection in the embodiments of this application refers to using a security protection method to protect user plane data/control plane signaling; the de-security protection in the embodiments of this application refers to restoring user plane data/control plane signaling according to the security protection method .
  • the security protection method here includes whether confidentiality protection and/or integrity protection are enabled, which are described here in a unified manner, and will not be repeated below.
  • the encryption key and the encryption algorithm can be used to encrypt and protect the user plane data/control plane signaling; when the integrity protection is enabled, the integrity protection key and the integrity protection algorithm can be used. Integrity protection for user plane data/control plane signaling.
  • the message integrity check code may also be used to perform integrity protection on the user plane data/control plane signaling. This is not specifically limited. The relevant description of the MIC refers to the subsequent embodiments, which will not be repeated here.
  • encryption protection and integrity protection of user plane data/control plane signaling may be performed first; The integrity protection is performed on the user plane data/control plane signaling first, and then the encryption protection is performed.
  • the embodiments of the present application do not limit the execution sequence of the encryption protection and the integrity protection, which are uniformly described here, and will not be repeated below.
  • the encryption key and the encryption algorithm can be used to decrypt the user plane data/control plane signaling; when the integrity protection is turned on, the integrity protection key and the integrity protection algorithm can be used to decrypt the data.
  • User plane data/control plane signaling performs integrity protection verification.
  • the integrity protection is not enabled, if the MIC is used to perform integrity protection on the user plane data/control plane signaling, correspondingly, the desired MIC may be used for the user plane data/control plane signaling.
  • Perform integrity protection verification which is not specifically limited in this embodiment of the present application. Wherein, the relevant description of the expected MIC refers to the subsequent embodiments, which will not be repeated here.
  • the security protection method used by the control plane of the PC5 connection is used to protect all or part of the parameters transmitted in the control plane signaling of the PC5 connection.
  • the security protection method used by the control plane connected by PC5 may include, for example, whether confidentiality protection and/or integrity protection of the control plane connected by PC5 is enabled.
  • the security protection method used by the user plane connected by PC5 may include, for example, whether confidentiality protection and/or integrity protection of the user plane connected by PC5 is enabled.
  • the security protection method used by the control plane connected to the PC5 may also be referred to as the security protection method used by the control plane signaling connected by the PC5; the security protection method used by the user plane connected by the PC5 is also It can be called the security protection method used by the user plane data connected by the PC5, which is uniformly described here, and will not be repeated below.
  • FIG. 1A a schematic diagram of a specific control plane system architecture to which the present application applies.
  • the network elements in the system architecture include terminal equipment (user equipment, UE).
  • FIG. 1A exemplarily draws four UEs, namely UE A, UE B, UE C, and UE D.
  • the system architecture also includes radio access network (RAN), access and mobility management function (AMF) network elements, session management function (session management function, SMF) network elements, user plane Function (user plane function, UPF) network element, unified data management (unified data management, UDM) network element, unified data repository (unified data repository, UDR) network element, application function (application function, AF) network element, data network (data network, DN), capability exposure network element (network exposure function, NEF) network element, 5G direct discovery name management function (5G direct discovery name management function, 5GDDNMF) network element, policy control function (policy control function, PCF) network element, ProSe application server, etc.
  • RAN radio access network
  • AMF session management function
  • SMF session management function
  • UPF user plane Function
  • UDM unified data management
  • UDR unified data repository
  • application function application function, AF
  • NEF network exposure function
  • 5G direct discovery name management function 5G direct discovery name management function, 5GDDNMF
  • policy control function policy control function
  • network elements such as AMF network elements, SMF network elements, UDM network elements, NEF network elements, and PCF network elements belong to the core network network elements in the 5th generation mobile networks (5G) network architecture.
  • 5G 5th generation mobile networks
  • Some core network elements are shown exemplarily, and the system architecture may also include other core network elements.
  • Terminal equipment is a device with wireless transceiver function, which can be deployed on land, including indoor or outdoor, handheld or vehicle; it can also be deployed on water (such as ships, etc.); it can also be deployed in the air (such as aircraft, balloons and satellite, etc.).
  • the terminal device may be a mobile phone (mobile phone), a tablet computer (pad), a computer with wireless transceiver function, a virtual reality (virtual reality, VR) terminal, an augmented reality (augmented reality, AR) terminal, an industrial control (industrial control) wireless terminals in ), wireless terminals in self-driving, wireless terminals in remote medical, wireless terminals in smart grid, wireless terminals in transportation safety , wireless terminals in smart cities, wireless terminals in smart homes, etc.
  • VR virtual reality
  • AR augmented reality
  • industrial control industrial control
  • the terminal device in this embodiment of the present application may be a terminal device capable of communicating in a proximity service (proximity service, ProSe) scenario, the terminal device has a proximity service application (ProSe application) function, and the terminal devices with the ProSe application function It can communicate through PC5 port.
  • ProSe proximity service
  • ProSe application proximity service application
  • the embodiments of this application involve three types of terminal devices, namely a first terminal device, a relay device, and a second terminal device.
  • the first terminal device can request other terminal devices (including the second terminal device) to provide proximity to the first terminal device.
  • the second terminal device can provide the proximity service for the first terminal device
  • the second terminal device provides the proximity service for the first terminal device.
  • the second terminal device and the first terminal device can communicate directly or communicate through a relay device.
  • the names of the second terminal device providing proximity services and the first terminal device requiring proximity services are different.
  • Two discovery scenarios are introduced here, namely open ProSe discovery and restricted proximity.
  • Service discovery (restricted ProSe discovery) scenario For the related descriptions of the open proximity service discovery scenario and the restricted proximity service discovery scenario, reference may be made to the prior art, and details are not repeated here.
  • a user A uses a terminal device A to play a game.
  • User A does not have a clear game partner, and only needs to "randomly" find a game partner.
  • This scenario is an open adjacent business scenario. If user A uses terminal device A to play games and has a clear partner, user A can "designate" a partner through terminal device A, and only the partner he designates can access the game, but not others.
  • This scenario is restricted proximity service Discover the scene.
  • the discovery mode in the discovery scene includes mode A (model A) or mode B (model B).
  • mode A model A
  • mode B model B
  • the difference between model A and model B is that in the discovery scenario, the terminal device initiates discovery in different ways.
  • model A The meaning of model A is "I am here".
  • the terminal equipment involved in model A is divided into the broadcasting UE (announcing UE) and the monitoring UE (monitoring UE).
  • the announcing UE broadcasts "I am here", and the monitoring UE receives the announcing UE. After the message broadcast by the UE, determine whether to establish a connection with the announcing UE according to whether it meets its own service requirements.
  • model B The meaning of model B is "Who is there?/Where are you?".
  • the terminal devices involved in model B are divided into the discoverer UE (discoveree UE) and the discoverer UE (discoverer UE).
  • the discoverer UE initiates a request, and the request Include specific information, such as who is there? /Where are you? ", after the discoveree UE receives the request initiated by the discoverer UE, it determines whether to reply to the request according to whether it can provide business services. If it responds, it means "I am here".
  • the open proximity service discovery scenario is only applicable to The discovery mode is applicable to model A, while the restricted proximity service discovery scenario is applicable to both model A and model B discovery modes.
  • the network side may determine the type of the first terminal device or the second terminal device according to the proximity service information reported by the first terminal device or the second terminal device to the network side
  • the discovery command included in the proximity service information reported by the first terminal device or the second terminal device to the network side can indicate whether the first terminal device or the second terminal device is an announcing UE or a monitoring UE; it is a responding terminal device ( response UE) is also a requesting terminal device (queryUE).
  • the announcing UE and the monitoring UE are the terminal devices at both ends in the above model A
  • the Response UE and the Query UE correspond to the discoveree UE and the discoverer UE in the above model B, respectively.
  • the second terminal device before providing the proximity service to the first terminal device, the second terminal device needs to verify the identity of the first terminal device to determine whether the second terminal device is a terminal device that really needs the proximity service. Specifically, the second terminal device may send and report the complete message code obtained from the first terminal device to the core network element or the 5G DDNMF network element, where the complete message code is generated based on the discovery key of the first terminal device , the discovery key of the first terminal device is generated by using the key generation parameter obtained from the core network element or the 5G DDNMF network element.
  • Verification is performed by the core network element or the 5G DDNMF network element based on the message integrity code reported by the second terminal device and the expected message integrity code calculated by the 5G DDNMF network element according to the discovery key of the first terminal device.
  • the second terminal device can also obtain the discovery key with the first terminal device from the core network element or the 5G DDNMF network element, and the second terminal device calculates the expected message integrity code for verification.
  • the first terminal device may also verify the identity of the second terminal device to determine whether the second terminal device is a terminal device that can truly provide proximity services.
  • the specific manner is similar to the manner in which the second terminal device verifies the identity of the first terminal device.
  • the main function of the RAN is to control the wireless access of users to the mobile communication network.
  • RAN is a part of a mobile communication system. It implements a wireless access technology. Conceptually, it resides between some device (such as a mobile phone, a computer, or any remote control machine) and provides a connection to its core network.
  • the AMF network element is responsible for the access management and mobility management of the terminal. In practical applications, it includes the mobility management function in the MME in the network framework of the LTE, and adds the access management function.
  • the AMF network element can also use Kamf to generate the discovery key of the terminal device, and send the discovery key of the terminal device to the 5GDDNMF network element or other network elements (such as ProSe application server).
  • Kamf is a root key of the terminal device, which is allocated by the network side (such as AMF network element) for the terminal device when the terminal device registers with the network, and is stored on the terminal device and the AMF side respectively.
  • the network side such as AMF network element
  • the SMF network element is responsible for session management, such as user session establishment.
  • the PCF network element is a control plane function provided by the operator, and is used to provide the policy of the session to the SMF network element.
  • the policies may include charging-related policies, QoS-related policies, authorization-related policies, and the like.
  • the UPF network element is the functional network element of the user plane, which is mainly responsible for connecting to the external network. It includes the related functions of the LTE serving gateway (SGW) and the public data network gateway (PDN-GW).
  • SGW LTE serving gateway
  • PDN-GW public data network gateway
  • the DN is responsible for the network that provides services for the terminal. For example, some DNs provide the terminal with the Internet access function, and other DNs provide the terminal with the short message function and so on.
  • the UDM network element can store the user's subscription information to implement HSS similar to 4G.
  • the UDM can determine the UE's user permanent identifier (subscription permanent identifier, SUPI) according to the UE's anonymized identifier or temporary identifier. .
  • the UDR network element is mainly used to store user subscription information, policy data, structured data for opening, and application data.
  • the AF network element can be a third-party application control platform or the operator's own equipment, and the AF network element can provide services for multiple application servers.
  • NEF network elements open the capabilities and events of other network elements to third-party partners or AF network elements. It provides a way for AF network elements to securely provide information to 3rd generation partnership project (3GPP) networks, NEF network elements can authenticate and authorize and assist in restricting AF network elements. In addition, the NEF network element can also convert the information exchanged by the AF network element with the information exchanged by the core network function network element.
  • 3GPP 3rd generation partnership project
  • the ProSe application server stores the user ID of the proximity service, and can also verify the terminal equipment in the discovery scenario. It is also possible to store a key preconfigured for the terminal device, which is a key related to proximity services.
  • the ProSe application server may be an AF network element, that is, an AF network element having the function of a Prose Application server.
  • the Prose application server and the UE can communicate on the user plane through the path of UE-RAN-UPF-AF.
  • the Prose application server can also communicate with other core network elements through NEF network elements.
  • the NEF network element communicates with the PCF network element.
  • 5GDDNMF network elements can allocate proximity service application ID (ProSe application ID) and proximity service application code (ProSe application code), and process proximity service application ID (ProSe application ID) and proximity service application code (ProSe application ID) ProSe application code).
  • 5GDDNMF network elements can communicate with the ProSe application server through the PC2 port in the restricted proximity service discovery scenario to process the authorization of the discovery request, assign the restricted proximity service application identifier (ProSe discovery UE ID) and the restricted proximity service application ID (ProSe discovery UE ID) The ProSe restricted code, and the mapping between the ProSe application identification (ProSe discovery UE ID) and the restricted ProSe code (ProSe restricted code).
  • both the proximity service application code (ProSe application code) and the restricted proximity service code (ProSe restricted code) can be used as the proximity service temporary identifier mentioned in the embodiment of the present application.
  • the 5GDDNMF network element adds a security function, which can verify the identities of terminal devices (such as the first terminal device and the second terminal device). For example, after receiving the message integrity code from the first terminal device reported by the second terminal device, the 5GDDNMF network element can use the discovery key of the first terminal device to generate the expected message integrity code. After determining the message integrity code and the expected message integrity After the codes are consistent, the second terminal device is notified that the verification of the first terminal device is successful.
  • a security function which can verify the identities of terminal devices (such as the first terminal device and the second terminal device). For example, after receiving the message integrity code from the first terminal device reported by the second terminal device, the 5GDDNMF network element can use the discovery key of the first terminal device to generate the expected message integrity code. After determining the message integrity code and the expected message integrity After the codes are consistent, the second terminal device is notified that the verification of the first terminal device is successful.
  • the security function added to the 5GDDNMF network element is used as an example for description.
  • This security function can also be added to other network elements, such as core network network elements or ProSe application Server, by other network elements and terminal equipment. interact to verify the identity of other end devices.
  • the core network elements also include an authentication server function (AUSF) network element, an authentication and key management for applications (AKMA) anchor function (AAnF) for applications ) network element, bootstrapping server function (BSF), etc.
  • the AUSF network element has an authentication service function.
  • the AUSF network element can use the Kausf of the terminal device to generate a discovery key of the terminal device, and the terminal The discovery key of the device is sent to the 5GDDNMF network element.
  • the AAnF network element can use Kakma to generate the discovery key of the terminal device, and send the discovery key of the terminal device to the 5GDDNMF network element.
  • the bootstrapping server function (BSF) network element can use Ks to generate the discovery key of the terminal device, and send the discovery key of the terminal device to the 5GDDNMF network element.
  • Kausf, Kakma, or Ks are also used as the root key for generating the discovery key of the terminal device.
  • These keys are the keys that the network side distributes for the terminal device when the terminal device registers to the network and are stored on the network side.
  • the key is the same as the key generated by the terminal device itself and stored on the terminal device side.
  • FIG. 1B is a schematic diagram of a specific user plane system architecture to which this application applies.
  • the user plane architecture mainly refers to the interaction between the UEA and the 5G DDNMF through the user plane, that is, the UE first accesses the 5GC to complete the user plane establishment, and then the UEA interacts with the 5G DDNMF through the user plane.
  • the control plane architecture mainly refers to the UE interacting with the 5G DDNMF through the control plane, that is, the UE first finds the AMF through the NAS message, and then the AMF forwards the NAS message. Give 5G DDNMF.
  • FIG. 2A is a UE-to-Network Relay (UE-to-Network Relay) system architecture.
  • the system architecture shows that a UE can access the network in 2 ways and 3 paths.
  • the two ways are the direct connection between the UE and the network (ie, the path #1 shown in the figure) and the way that the UE accesses the network through a relay (ie, the path #2 and the path #3 shown in the figure).
  • FIG. 2B shows an architecture in which UE-1 and UE-2 communicate through a relay.
  • the relay (Relay) is used as a medium for communication between UE-1 and UE-2. Through the relay, UE-1 and UE-2 can communicate.
  • the security protections of the links at both ends of the relay are respectively: the first PC5 link between UE-1 and the relay has user plane confidentiality protection enabled, and user plane integrity protection is enabled; but the relay The second PC5 link between UE-2 is that the user plane confidentiality protection is not enabled, and the user plane integrity protection is enabled.
  • the confidentiality protection of user plane data is only performed on the first PC5 link, that is, an attacker can illegally obtain user plane data from the link between the relay and UE-2. Therefore, UE- The confidentiality protection of the first PC5 link between 1 and the relay is meaningless, and the processing performance of UE1 and the relay is also wasted. It can be seen that the current UE-to-Network Relay (UE-to-Network Relay) communication method still has the problem of insufficient security.
  • an embodiment of the present application provides a method for secure communication.
  • the method includes: the relay device determines, according to the user plane protection method of the second PC5 link between the relay device and the second terminal device, the connection between the relay device and the second terminal device.
  • the user plane protection method of the first PC5 link between a terminal device thereby ensuring the consistency of the user plane security protection results of the two links.
  • the identifications that may be involved include but are not limited to at least one of the following:
  • the terminal identifier may include an international mobile subscriber identification number (IMSI), a permanent equipment identifier (PEI), a user permanent identifier (SUPI), a user concealed identifier (subscriber concealed identifier, SUCI), temporary mobile subscriber identity (TMSI), IP multimedia public identity (IMPU), media access control (MAC) address, IP address, mobile phone number or globally unique At least one of the temporary UE identity (globally unique temporary UE identity, GUTI).
  • IMSI international mobile subscriber identification number
  • PEI permanent equipment identifier
  • SUPI user permanent identifier
  • SUCI user concealed identifier
  • TMSI temporary mobile subscriber identity
  • IMPU IP multimedia public identity
  • MAC media access control
  • the terminal identifier includes only IMSI, or only PEI and SUPI, or only includes PEI, TMSI and IMPU, or includes IMSI, PEI, SUPI, SUCI, TMSI, IMPU, MAC address, IP address, mobile phone number and GUTI, etc. , which is not limited here.
  • the UEID is uniformly used to represent the terminal identifier.
  • PEI is the fixed identification of the terminal equipment
  • IMSI is the unique permanent identification of the user in the LTE system
  • SUPI is the permanent identification of the user in the 5G system
  • SUCI is the user identification obtained by encrypting the SUPI.
  • the secure communication method provided by the embodiments of the present application includes two parts, the first part: a security policy configuration method; the second part: a relay device or a second part.
  • the terminal device determines the user plane security protection method and the control plane security protection method of the PC5 link.
  • the two parts are described below:
  • a method for configuring a security policy provided by an embodiment of the present application is described, and the method includes:
  • Step 301 the terminal device sends a NAS message to the AMF, the message is used to trigger the AMF to provide preset data to the terminal device, and the preset data is used for establishing a PC5 link in a subsequent proximity communication (prose) scenario.
  • the terminal device can send the NAS message to the AMF through the RAN.
  • the NAS message may be a security policy provisioning data request (UE policy provisioning request) message of the terminal device.
  • the message may include the terminal identification of the terminal device (such as 5G-GUTI), and the short-range communication role indication information of the terminal device (such as remote indication and/or relay indication).
  • the terminal identifier is used for the network side device to determine which terminal device initiates the request.
  • the network device may determine the SUPI of the UE through the 5G-GUTI, and obtain network-side data of the UE according to the SUPI of the UE, such as subscription data in a proximity (Prose) communication scenario.
  • Prose proximity
  • the proximity communication role indication information is used by the network side device to determine which type of UE the UE can access to the network in the Prose scenario. For example, whether the UE accesses the network as a common UE; or it can access the network as a relay serving other UEs, so as to forward data between the access network for other UEs (or forward and communicate with another UE for other UEs) data between UEs); it can still access the network as a remote UE, and a remote UE means that a UE needs to pass through a relay to connect with another UE (or network) and exchange data. In other words, the remote UE cannot connect to the network (or to another UE) without the assistance of the relay UE.
  • the first possible implementation method: setting the short-range communication role indication information to "0" means that it does not need to be used as a relay.
  • "0" can be understood in two ways on the network side: (1), the UE can be used as a remote At this time, it can be understood that all UEs can be used as remote UEs; (2), the UE can neither be used as remote UEs nor relays. This embodiment does not limit the specific understanding.
  • Setting it to "1” means it can act as a relay. At this time, "1" can be understood in two ways on the network side: (1) the UE can only be used as a relay; (2) the UE can be used as both a remote UE and a relay. This embodiment does not limit the specific understanding.
  • the second possible implementation method setting the proximity communication role indication information to "00" means that it does not need to be a remote UE or a relay; setting it to "01” means that it cannot be used as a remote UE, but can be used as a remote UE.
  • Relay set to "10” means that it can be used as a remote UE, but not a relay; set to "11” means that it can be used as both a remote UE and a relay.
  • the short-range communication role indication information may also be a string, such as "remote (remote)", “relay (relay)”, “remote and relay (remote&relay)”.
  • This embodiment does not limit the number of character strings that can appear at the same time. That is to say, in the case where only two strings of "remote” and “relay” can be used, these two strings can be transmitted at the same time, indicating that the UE can play two roles at the same time. If only one appears, it means that it can only be used as one role.
  • remote means that the UE can only act as a remote UE
  • relay means that the UE can only act as a relay UE
  • remote and Relay (remote & Relay)" The UE can act as both a remote UE and a relay UE.
  • Step 302 the AMF checks the authorization information of the terminal device.
  • the AMF needs to check whether the identity indication information transmitted by the terminal device is legal, that is, whether it can be a remote UE (Remote UE), or, the AMF needs to check whether the terminal device can be used as a relay, or, when the near When the distance communication role indication information indicates that the terminal device can act as both a remote UE and a relay, the AMF needs to check the above two identities at the same time.
  • the identity indication information transmitted by the terminal device is legal, that is, whether it can be a remote UE (Remote UE), or, the AMF needs to check whether the terminal device can be used as a relay, or, when the near
  • the distance communication role indication information indicates that the terminal device can act as both a remote UE and a relay
  • the AMF needs to check the above two identities at the same time.
  • an implementation manner of checking authorization may be: the AMF interacts with the UDM, and obtains the subscription data in the Prose communication scenario of the terminal device from the UDM.
  • the AMF determines whether the terminal device can act as a relay and/or a remote UE according to the subscription data.
  • the AMF may also acquire the subscription data of the terminal device from the PCF, or acquire the subscription data of the terminal device from the Prose application server through the capability opening network element, which is not limited in this embodiment.
  • the AMF may obtain the checking result of the authorization information of the terminal device from the PCF. That is, the PCF interacts with the UDM, and obtains the subscription data in the Prose scenario of the terminal device from the UDM. The PCF determines whether the terminal device can act as a relay and/or a remote UE according to the subscription data, and then the PCF sends the check result to the AMF.
  • the PCF may also acquire the subscription data of the terminal device from the Prose application server or other devices through the capability opening network element, which is not limited in this embodiment.
  • Step 303 After the AMF has successfully checked the authorization of the terminal device, the AMF sends a request message to the PCF, where the message is used to request the security policy preset data of the terminal device.
  • the AMF sends a (pcf_UEPolicyControl_Update) message to the PCF, where the message includes the proximity communication role indication information of the terminal device (such as remote UE indication/relay UE indication).
  • the message also carries near-proximity (Prose) communication related information of the terminal device (such as UE's Prose identity information: Prose User ID, Prose application information, Prose APP ID, etc.).
  • Step 304 the PCF determines the security policy of the terminal device.
  • the PCF determines the security policy used by the terminal device as a relay (relay identity); When it can be used as a remote UE, the PCF determines the security policy used by the terminal device as a remote UE (remote identity). When determining that the terminal device is a common UE, the PCF determines the security policy used by the terminal device as a common UE.
  • the security policy may include a PC5 control plane security policy and/or a PC5 user plane security policy.
  • the PCF can respectively determine the security policy used by the terminal device as a relay and the security policy used by the remote UE.
  • the PCF may further interact with other network elements (such as 5G DDNMF) to obtain more Prose-related information of the terminal device.
  • network elements such as 5G DDNMF
  • Prose APP Code Prose APP Code is used for discovery between UEs.
  • Step 305 the PCF sends a response message to the AMF, where the response message includes the security policy of the terminal device.
  • the PCF replies to the AMF a Nafm_Communication_N1N2MessageTransfer message, where the message includes at least one type of a security policy of a common identity and a security policy of a non-ordinary identity.
  • the non-common identities include relay identities or remote identities.
  • the security policy can be used not only for ordinary access, but also for remote identity and/or relay identity access. (if the UE supports these identities).
  • the message carries two security policies, one represents the security policy used by ordinary identities, and the other represents the security policy used by non-ordinary identities.
  • the message if the message carries three security policies, they represent the security policy used by the common identity, the security policy used by the remote identity, and the security policy used by the relay identity, respectively.
  • the remote identities may also belong to a type of ordinary identities, and in this case, the non-common identities only include relay identities. If not all UEs can use the remote identity, the non-ordinary identity includes the relay identity and the remote identity.
  • Step 306 the AMF forwards the security policy of the terminal device to the UE.
  • Step 307 the terminal device receives the security policy and saves it in the local device.
  • PCF can also be other network elements that can provide security.
  • the so-called network element that provides security policies is the network element or functional entity that allocates policies on the network side, such as PCF in 5G and (policy and charging) in 4G. rules function) Policy and Charging Rules Functional Unit, PCRF), and network elements that inherit related functions in future networks.
  • the security policy of the terminal device determined by the PCF may have multiple granularities.
  • it can be PCF granularity, that is, all terminal devices requesting the PCF correspond to the same security policy; another example, it can be UE granularity, that is, different terminal devices may correspond to different security policies; another example, it can be APP granularity , that is, the terminal devices corresponding to different APP IDs may correspond to different security policies; for another example, it may be UE+APP granularity, that is, different UE+APP binding relationships, the terminal devices may correspond to different security policies.
  • security policies can be divided into security policies for common identities and security policies for non-ordinary identities, the security policies of terminal devices with different identities may be the same or different.
  • security policies corresponding to terminal devices with two identities, the remote UE and the relay UE may be the same or different.
  • the security policy can also be stored after being bound with the identities of the remote or the relay, that is, the security policies of the two identities are stored.
  • the security policy of UE1 includes the security policy of the remote identity and the security policy of the relay identity.
  • the security policy of common identity includes control plane confidentiality protection as PREFERRED, control plane integrity protection as REQUIRED, user plane confidentiality protection as NOT NEEDED, and user plane integrity protection as REQUIRED; non-ordinary identity security policies include control plane
  • the confidentiality protection is PREFERRED, the control plane integrity protection is PREFERRED, the user plane confidentiality protection is PREFERRED, and the user plane integrity protection is PREFERRED.
  • the security policies of different identities of UE1 are the same, the security policies of only one identity may also be stored.
  • control plane confidentiality protection is PREFERRED
  • control plane integrity protection is PREFERRED
  • user plane confidentiality protection is PREFERRED
  • user plane integrity protection is PREFERRED
  • a method for ensuring link establishment is: in the configuration method of the security policy, the security policy used by common identities (similar to one-to-one communication in V2X)
  • the security policy used in the process) can include two states: on and off.
  • the control plane confidentiality protection is enabled
  • the control plane integrity protection is optional
  • the user plane integrity protection is disabled
  • the user plane confidentiality protection is optional.
  • the security policy used by non-ordinary identities only contains optional security policies, that is, only contains the "PREFERRED” state, and does not contain the "REQUIRED” state and "NOT NEEDED" state.
  • the advantage of this is to ensure that the message link in the communication scenario with relay can be established. Because in the prior art, if the security policies of any two between UE-1, UE-2 and the relay shown in FIG. 2B are in diametrically opposite states (for example, the control plane confidentiality security policy of UE-1 is REQUIRED state, UE-2's control plane confidentiality security policy is NOT NEEDED state), then UE-2 or the relay will release the connection, so the link cannot be established. Therefore, if the security policy of the relay includes two states: not enabled and optional, the message link in the relay scenario may not be established because the relay has a clear security policy.
  • Another way to ensure link establishment is that UEs with common attributes are assigned the same security policy but do not contain a "PREFERRED" state. Having a common attribute means that the service granularity is the same, or other attribute information is the same, and the other attribute information may be some kind of attribute information that can classify a part of UEs together. In this case, the relay will only be used to establish services within the range of these UEs, so that it can be ensured that the link cannot be established due to the relay.
  • the PCF further stores at least one of a security endpoint policy and a security algorithm policy
  • the security policy of the terminal device determined by the PCF may also include the security endpoint policy of the terminal device, the terminal device security policy, and the terminal device security policy. At least one of the security algorithm policies.
  • the security endpoint policy is whether the security endpoint should or prefer to be placed on the relay, or should not or not be placed on the relay. Among them, “should” is a mandatory action that must be satisfied. The meaning of "tendency” is preferred, and may not be satisfied.
  • bit information when the bit information is only 1 bit, and the value is 0, it means that the security endpoint should or is inclined to be placed on the relay, and when the value is 1, it means that the security endpoint should not or is not inclined to be placed on the relay.
  • bit information when the bit information is at least 2 bits, 00 indicates that the security endpoint must be placed on the relay, 01 indicates that the security endpoint tends to be placed on the relay, and 10 indicates that the security endpoint tends not to be placed on the relay. 11 means that the security endpoint must not be placed on the relay.
  • the strings "end”, “hop”, and “prefer” can also be used to indicate that they must not be placed on the relay, must be placed on the relay, and tend to be placed on the relay.
  • the security algorithm strategy refers to whether or not to use a 128-bit algorithm or a 256-bit algorithm. It can be represented by bits indicating information, or it can be represented by strings.
  • bit information when the bit information is only 1 bit, 0 means that the 128bit algorithm should be used or preferred, and 1 means that the 256bit algorithm should be used or preferred.
  • bit information when the bit information is at least 2 bits, 00 means that the 128bit algorithm must be used, 01 means that the 128bit algorithm must be used, 10 means that the 256bit algorithm must be used, and 11 that the 256bit algorithm must be used.
  • the strings 128, 256, and prefer can be used to indicate that the 128-bit algorithm must be used, the 256-bit algorithm must be used, or both.
  • the above security endpoint policy and security algorithm policy can use the same granularity information as the security policy, that is to say, these policies have the same granularity as the security policy; they can also use different granularity information from the security policy, that is, these policies are the same as the security policy. different granularity. This embodiment makes no provision.
  • the granularity information of the security policy refers to the scope that the security policy can function. For example, when the security policy is APP ID granularity, it means that the security policy corresponding to a certain APP ID cannot be used on other APP IDs. For another example, when the security policy is UE granular, it means that all services of the UE use the same security policy.
  • the present invention does not limit the PCF to store a single security policy for the UE, that is, the PCF may only store the security policy of UE granularity for some UEs. It is also possible to store only APP ID granularity security policies for the UE. Different granularity of security policies can also be stored for the UE. For example, to store the security policy corresponding to an APP ID and the corresponding security policy other than this APP ID for a UE, at this time, the corresponding security policy other than this APP ID can be understood as UE granularity.
  • the response message may also carry granularity information of the security policy.
  • each Prose APP ID has a corresponding security policy.
  • the following possible representation methods appear.
  • the following representation methods can be used for the storage of UE and PCF, for steps 305
  • the method of expressing the transmitted Xinyuan in the message, the embodiment of the present application does not limit its usage scenario.
  • ⁇ General identity security policy, non-ordinary identity security policy (Prose APP ID-1 security policy, Prose APP ID-2 security policy, default security policy) ⁇ ; this method means that there is an ordinary Identity security policy.
  • This security policy is used when the UE does not act as a remote UE and a relay UE. In the case that all UEs can be used as remote UEs, the security policy is a security policy only used when the UEs are not used as relay UEs. It also includes a non-ordinary identity security policy with Prose APP ID 1, a non-ordinary identity security policy with Prose APP ID 2, and a default non-ordinary identity security policy.
  • the security policy of Prose APP ID-1 can include at least one security policy of non-ordinary identities. For example, for Prose APP ID-1, it can only include The security policy of the relay identity corresponding to the Prose APP ID-1 can also include both the security policy of the relay identity corresponding to the Prose APP ID-1 and the security policy of the remote identity of the Prose APP ID-1. It should be noted that the method Prose APP ID represents the granular information corresponding to the security policy. Therefore, it can be understood that if the PC5 security granularity is not the granularity of the Prose APP ID, the Prose APP ID can be replaced with the granularity corresponding to the security policy. For example, if the UE granularity is used, the Prose APP ID can be changed to SUPI.
  • the security policy of Prose APP ID-1 contains only one security policy, it can be understood that the security policy can be used by two identities.
  • non-ordinary identity security policy (Prose APP ID-1 relay identity security policy, Prose APP ID-2 remote identity security policy, default security policy ) ⁇
  • Security policies for non-ordinary identities outside the At this time if the UE can use the remote identity under Prose APP ID-1, the security policy of the remote identity is the default non-common identity security policy. Similarly, if Prose APP ID-2 can use relay identity, the security policy of its relay identity is the default non-ordinary identity security policy.
  • Prose APP ID-1 (security policy of ordinary identity, security policy of non-ordinary identity)
  • ⁇ Prose APP ID-2 (security policy of ordinary identity, security policy of non-ordinary identity)
  • default security Strategy ⁇ in this representation method, Prose APP ID-1 and Prose APP ID-2 represent granularity information.
  • This method indicates what the security policy of ordinary identity and the security policy of non-ordinary identity can be used in Prose APP ID-1, and what the security policy of ordinary identity and the security policy of non-ordinary identity can be used by Prose APP ID-2. And the default security policy that any identity of other apps can use. For a detailed description, please refer to the description in method 1).
  • ⁇ Prose APP ID-2 (security policy of ordinary identity, security policy of non-ordinary identity), default security policy of non-ordinary identity, default security policy of ordinary identity ⁇ .
  • This method represents the security policy of ordinary identities and the security policy of non-ordinary identities that can be used by Prose APP ID-2, and the default security policies that can be used by ordinary identities and the default security policies that can be used by non-common identities under other Prose APPs. For a detailed description, please refer to the description in method 1).
  • this method represents the security policy used by the normal identity of the UE and the security policy used by the non-common identity in the case of UE granularity.
  • the security policy of the non-common identity may include at least one of the security policy of the remote identity and the security policy of the relay identity. Which one to carry should be determined according to the identity indication information carried when the UE requests. If both identities are carried, the security policies of the two non-common identities need to be carried.
  • this representation method represents the UE's normal identity security policy and relay identity security policy in the case of UE granularity. This representation method is applicable to all UEs having a remote identity, and the remote identity is one of the common identities, that is, the security policy of the common identity can be reused.
  • the security policy of the non-common identity includes at least one of the security policy of the relay identity and the security policy of the remote identity.
  • the PCF configures the security policy for the terminal device.
  • the security policy of the relay is preferentially configured as the security policy of PREFERRED, which can ensure the relay PC5 link
  • the establishment of the security policy also includes granular information to ensure the scope of the security policy. It should be noted that there are various binding relationships between security policies and granularities, and the embodiments of the present application only provide some reference examples, and the embodiments of the present application do not limit the ways of using security policies and granularities.
  • an embodiment of the present application provides a method for secure communication.
  • FIG. 4 is a flowchart of the method.
  • the method is applied to the network architecture shown in FIG. 2A or FIG. 2B as an example.
  • the method may be performed by a first communication device, which may be a terminal device, or a communication device capable of supporting the functions required by the terminal device to implement the method, for example, a component included in the terminal device, or a component in the terminal device. Chip system, etc.
  • FIG. 4 is a schematic flowchart of a secure communication method provided by an embodiment of the present application, and the method may include the following steps.
  • Step 401 The first terminal device broadcasts a first direct communication request (direct communication request, DCR) message.
  • the first DCR message carries the PC5 control plane security policy of the first terminal device.
  • the first DCR message may further carry a security termination point policy of the first terminal device, where the security termination point policy is used to determine whether the security termination point is on the relay. For example, when the first DCR message carries the "hop-by-hop" security termination policy, the security termination point is on the relay; when the first DCR message carries the "end-to-end” security termination policy , the secure endpoint is not on the relay.
  • a security algorithm policy may also be included in the first DCR message.
  • the PC5 control plane security policy of the first terminal device carried in the first DCR message is the PC5 control plane security policy of the remote identity.
  • the PC5 control plane security policy of the first terminal device carried in the first DCR message is obtained from the network side according to the embodiment shown in FIG. 3 .
  • PC5 control plane security policy is obtained from the network side according to the embodiment shown in FIG. 3 .
  • the first DCR message may also carry granularity information (such as APP ID) of the PC5 control plane security policy of the first terminal device, and the granularity information is used for PC5 control of the first terminal device scope of the security policy.
  • granularity information such as APP ID
  • the first DCR message is a broadcast message and will be received by different relays.
  • the PC5 control plane security policy may include at least one of a normal identity PC5 control plane security policy and a non-normal identity PC5 control plane security policy.
  • the message may also carry the PC5 control plane security algorithm supported by the first terminal device, so that the second terminal device can determine the PC5 control plane security algorithm of the second PC5 link.
  • Step 402 after receiving the first DCR message, at least one relay sends a second DCR message to the second terminal device.
  • the second DCR message is generated and sent by at least one relay.
  • the second DCR message may be directly the first DCR message, that is, at least one relay directly forwards the first DCR message to the second terminal device.
  • the second DCR message may also include relay related information and related information of the first terminal device.
  • the relevant information of the first terminal device comes from the first DCR message.
  • the related information of the first terminal device may be the entire first DCR message or a part of the first DCR message.
  • the relevant information of the relay may include the PC5 control plane security policy of the relay, the PC5 control plane security algorithm of the relay, and the like.
  • the relay before forwarding the second DCR message to the second terminal device, the relay needs to first determine whether the relay can serve the first terminal device. It should be noted that the judging process may take place before the above step 401, and the judging process may also take place after the above step 401. For example, before the first terminal device sends the second DCR message, the relay can determine whether it can serve the first terminal device through the discovery process, and if it can serve the first terminal device, the relay will receive the first DCR message and generate a second DCR message. DCR message, if not, the relay directly rejects the first DCR message.
  • the relay after receiving the first DCR message, the relay first determines whether it can serve the first terminal according to the information in the message, and if so, the relay receives the first DCR message. A DCR message is generated and a second DCR message is generated. If not, the relay directly rejects the first DCR message. For example, it is judged by the application layer ID information carried in the message.
  • This embodiment is not limited, and the number of at least one relay may be one, or more than two.
  • At least one relay judges whether the control plane security policy of the first terminal device can be supported, and if so, generates a second DCR message and sends the second DCR message to the second terminal device. If not supported, there is no need to generate a second DCR message for the first terminal device. Specifically, at least one relay judges whether the PC5 control plane confidentiality protection policy and the PC5 control plane integrity protection policy of the relay conflict with the PC5 control plane confidentiality security policy of the first terminal device.
  • the first terminal device cannot select PC5 control plane confidentiality A relay whose security protection is REQUIRED, or the PC5 control plane integrity protection is NOT NEEDED.
  • NOT NEEDED and REQUIRED are in conflict.
  • the relay may also send at least one of the relayed PC5 control plane security policy, security endpoint policy and security algorithm policy to the second terminal device.
  • the above-mentioned bearer modes such as the relay-related security policy are different due to different formats of the second DCR message.
  • the above-mentioned relay-related security policy can be carried in the DCR message forwarded by the relay to the second terminal device, or, when When the first DCR message or a part of the first DCR message is used as a container (content), an IE or some IEs of the second DCR message, the above-mentioned relay-related security policy can be carried in its unrelated first DCR message.
  • the second DCR message may also carry the control plane security algorithm supported by the first terminal device and/or the control plane security algorithm supported by the relay.
  • the specific carrying method reference may be made to the above-mentioned relevant description on the carrying method of the security policy.
  • Step 403 the second terminal device determines a relay for serving the first terminal from the at least one relay.
  • this step 403 is an optional step.
  • the second terminal device only needs to judge whether the relay supports the service, and if so, determine that the relay is a relay that can serve the first terminal. For example, the second terminal device determines whether it is interested in the application information carried in the message.
  • the second terminal device when there are more than two relays forwarding the DCR message to the second terminal device, the second terminal device, according to the received PC5 control plane security policy of the first terminal device, at least two relays
  • the PC5 control plane security policy of the second terminal device, the PC5 control plane security policy of the second terminal device, the security termination point policy of the first terminal device, the security termination point policy of at least two relays, the security termination point policy of the second terminal device, the At least one of a security algorithm policy of a terminal device, a security algorithm policy of at least two relays, and a security algorithm policy of a second terminal device, and a relay serving the first terminal is determined from the at least two relays.
  • the second terminal device may receive forwarding messages from different relays according to the order of the second terminal device.
  • a relay serving the first terminal is determined from at least two relays.
  • the second terminal device can use the PC5 control plane security policy of a terminal device and the PC5 control plane security policy of the first relay , the PC5 control plane security policy of the second terminal device, the security termination point policy of the first terminal device, the security termination point policy of the first relay, the security termination point policy of the second terminal device, the security algorithm policy of the first terminal device , at least one of the security algorithm policy of the first relay and the security algorithm policy of the second terminal device, to determine whether the first relay can be used to establish a PC5 link. If so, determine that the first relay is the target relay, which can be used to establish the PC5 link; if not, then perform the above judgment on other relays in sequence according to the receiving time sequence.
  • the second terminal device may randomly select a second DCR message sent by a relay for judgment. And so on until the target relay that meets the conditions is determined.
  • This embodiment of the present application does not limit the specific selection sequence of the determined relays.
  • the second terminal device may determine the target relay in at least one of the following manners.
  • the second terminal device determines the target relay according to the security termination point of the second terminal device.
  • the second terminal device can only select from at least two relays. Select a target relay that supports "hop-by-hop" or supports the security policy of PREFERRED. For another example, if the pre-configured security endpoint policy of the second terminal device or obtained from the network side is point-to-point (End-to-End), then the second terminal device can only select from at least two relays. A security policy target relay that supports End-to-End or supports PREFERRED.
  • the second terminal device determines the relay according to the PC5 control plane security policy of each terminal device in each combination.
  • the first relay and the second relay send the second DCR message to the second terminal device, then there are two combinations, the first combination includes the first terminal device, the first middle A relay and a second terminal device; the second combination includes a first terminal device, a second relay and a second terminal device.
  • the PC5 control plane security policy preconfigured by the second terminal device includes a PC5 control plane security policy that is not enabled (meaning that at least one of the control plane confidentiality protection and the control plane integrity protection is NOT NEEDED), then The second terminal device cannot select a relay that conflicts with the PC5 control plane security policy preconfigured by the second terminal device (meaning that at least one of the corresponding control plane confidentiality protection and control plane integrity protection is REQUIRED).
  • the PC5 control plane security policy of the second terminal device is that the PC5 control plane confidentiality protection is NOT NEEDED and the PC5 control plane integrity protection is REQUIRED
  • the second terminal device cannot select the PC5 control plane confidentiality protection to be REQUIRED, Or the PC5 control plane integrity protection is NOT NEEDED relay.
  • the second terminal device first determines that the security termination point is hop-by-hop, then selects the relay according to the above steps. Conversely, if the preconfigured security endpoint of the second terminal device is End-to-End security, it is not necessary to refer to the PC5 control plane security policy of the relay when selecting the relay. At this time, the control plane security protection method with the first terminal device may be determined according to Section 5.3.3.1.4.3 in the 3GPP standard TS 33.536.
  • the second terminal device determines the relay according to the PC5 control plane security policy of each device in each combination, the PC5 user plane security policy of the second terminal device and the PC5 user plane security policy of the second terminal device.
  • the second terminal device can refer to the PC5 using the second terminal device when selecting the relay.
  • User plane security policy includes the following aspects: 1) If the control plane confidentiality protection is activated, the user plane confidentiality protection can be activated or not. 2) If the control plane integrity protection is activated, the user plane integrity protection can be activated or not. 3) If the control plane confidentiality protection is not activated, then the user plane confidentiality protection is not activated. 4) If the control plane integrity protection is not activated, the user plane integrity protection is not activated.
  • principle 1 if the PC5 user plane security policy of the second terminal device has the "REQUIRED” state, then the PC5 control plane security policy of the relay selected by the corresponding second terminal device should also be in the "REQUIRED” state.
  • the second terminal device can only select the control plane confidentiality protection and/or control of PC5.
  • Principle 2 If the PC5 user plane security of the second terminal device has the "NOT NEEDED" status, then the PC5 control plane security policy of the relay selected by the corresponding second terminal device cannot be “REQUIRED”. Exemplarily. If the user plane confidentiality protection and/or the user plane integrity protection of PC5 is in the "NOT NEEDED” state, the second terminal device can only select that the control plane confidentiality protection and/or control plane integrity protection of PC5 is not "REQUIRED” "relay.
  • the second terminal device determines the relay according to the security algorithm policy of the relay and the security algorithm policy of the second terminal device.
  • the second terminal device when the second terminal device only supports 128-bit algorithm, the second terminal device cannot select a relay that only supports 256-bit algorithm; in principle 2, the second terminal device only supports 256-bit algorithm. In the case of the -bit algorithm, the second terminal device cannot select a relay that only supports the 128-bit algorithm.
  • this embodiment of the present application does not limit the execution sequence of the three policies, namely the PC5 user plane security policy, the PC5 control plane security policy, and the security endpoint policy. Implementation, the embodiments of the present application also do not limit the combination and use methods of the three security policies.
  • the security endpoint policy is specified by the standard, that is, the standard stipulates that only hop-by-hop or end-to-end can be used, then the security endpoint policy is not required, and other The steps should be executed in accordance with the relevant regulations by default.
  • the security termination point is located at on the target relay.
  • Step 404 after the second terminal device determines the first relay, initiates an authentication process with the first relay.
  • step 404 is an optional step in this embodiment.
  • the function of the authentication process is to complete the mutual trust between the second terminal device and the first relay, and to generate a root key for protecting the keys of the control plane and the user plane.
  • a specific description please refer to the description in 5.3.3.1.4.3 of the standard TS33.536 chapter.
  • the second terminal device sends a Direct Auth and Key Establishment message to the first relay, triggering an authentication process between the second terminal device and the first relay.
  • the first relay may determine that the Direct Auth and Key Establishment message is sent to itself, and after receiving the message, the first relay will initiate an authentication and key generation process with the second terminal device.
  • the first relay can be determined in at least two ways as follows. One way is that: the Direct Auth and Key Establishment message includes indication information, or the indication information is sent to the second terminal device along with the Direct Auth and Key Establishment message ( At this time, it can be understood that the indication information is outside the Direct Auth and Key Establishment message), and the indication information is used to indicate that authentication and key distribution are performed between the second terminal device and the first relay. For example, a bit is used to indicate whether the message is sent to the first relay or to the first terminal device.
  • the first relay determines that authentication and key distribution are performed between the second terminal device and the first relay through the format of the Direct Auth and Key Establishment message. For example, if Direct Auth and Key Establishment is sent to the first relay as part of a container, the first relay will send the Direct Auth and Key Establishment message in the container to the first terminal device. At this time, the first relay may not Knowing the contents of the container, that is, not knowing it is the Direct Auth and Key Establishment message. That is to say, the first relay just sees the container and forwards it. For another example, if Direct Auth and Key Establishment is directly sent to the first relay, then the first relay automatically determines that the message is sent to the first relay, not the first terminal device.
  • the first relay does not need to determine the Direct Auth and Key Establishment message Whether it is sent to itself or to the first terminal device. That is, in the case of hop-by-hop, the first relay will know that the Direct Auth and Key Establishment message is sent to itself, and in the case of End-to-End, the first relay will know the Direct Auth and Key The Establishment message is sent to the first terminal device. Knowing the method is not limited The embodiment of the present application is not limited.
  • Step 405 the second terminal device determines the PC5 control plane security protection method of the second PC5 link, and selects the PC5 control plane security algorithm of the second PC5 link.
  • This step may occur after step 403 and before step 404 .
  • the second terminal device may determine the PC5 control plane security protection method of the second PC5 link in at least one of the following manners:
  • the second terminal device determines the PC5 control plane security protection method of the second PC5 link according to the PC5 control plane security policy of the first relay and the PC5 control plane security policy of the second terminal device. For the specific determination method, refer to the description in 5.3.3.1.4.3 of the standard TS33.536 chapter.
  • the PC5 control plane integrity protection of the first relay is optional, the PC5 control plane confidentiality protection of the first relay is enabled, the PC5 control plane integrity protection of the second terminal device is enabled, and the second terminal device is enabled.
  • the PC5 control plane confidentiality protection is turned on, and the second terminal device determines that the PC5 control plane integrity protection of the second PC5 link is turned on, and the PC5 control plane confidentiality protection of the second PC5 link is turned on.
  • Mode 2 In addition to the PC5 control plane security policy of the first relay and the PC5 control plane security policy of the second terminal device, the second terminal device also determines the second PC5 link in combination with the PC5 control plane security policy of the first terminal device.
  • the PC5 control plane security protection method In this way, the PC5 control plane security protection method between the first relay and the second terminal device and the PC5 control plane security protection method between the first relay and the first terminal device may be the same.
  • control plane integrity protections when one of the control plane integrity protections is REQUIRED, it is determined that the control plane integrity protection needs to be activated.
  • REQUIRED it is determined that the control plane confidentiality protection needs to be activated.
  • One of the control plane integrity protection is NOT NEEDED, and it is determined that the control plane integrity protection does not need to be activated.
  • the control plane confidentiality protections are determined to not need to be activated.
  • the plane integrity protection of all control planes is PREFERRED, it is determined that the control plane integrity protection can be activated or not.
  • one of the control plane confidentiality protections is PREFERRED, it is determined that the control plane confidentiality protection can be activated or not.
  • the second terminal device determines the PC5 control plane security protection according to the PC5 control plane security policy of the first relay and the PC5 control plane security policy of the second terminal device, and can also be combined with the PC5 user plane security policy of the second terminal device. method.
  • the second terminal device determines that the PC5 user plane security policy of the second terminal device has a "REQUIRED" state
  • the PC5 control plane security policy of the first relay may support REQUIRED (for example, PREFEER, or REQUIRED)
  • the PC5 control plane security policy of the second terminal device can support REQUIRED (for example, PREFEER, or REQUIRED)
  • the PC5 control plane security policy of the second PC5 link is determined to be in an open state.
  • the second terminal device determines that the control plane integrity protection is enabled.
  • the method for determining the control plane integrity protection also needs to refer to the user plane confidentiality protection of the second terminal device. That is, if the user plane confidentiality protection of the second terminal device is REQUIRED at this time, the first control plane integrity protection method is determined to be enabled, and the control plane confidentiality protection is REQUIRED; if the user plane confidentiality protection of the second terminal device at this time is If the protection is PREFERRED or NOT NEEDED, the second terminal device may determine that the control plane integrity protection is enabled or disabled, and the control plane confidentiality protection may be determined to be enabled or disabled. If the user plane integrity protection set by the second terminal is NOT NEEDED, the determination method of the control plane integrity protection also needs to refer to the user plane confidentiality protection of the second terminal device.
  • the second terminal device can control the The plane integrity protection is determined to be enabled or disabled, and the control plane confidentiality protection is determined to be enabled or disabled.
  • the second terminal device may select the PC5 control plane security algorithm.
  • the security algorithm includes a confidentiality protection algorithm and/or an integrity protection algorithm. If it is determined that the PC5 control plane integrity protection of the second PC5 link needs to be activated, a non-empty PC5 control plane integrity security algorithm needs to be selected; if it is determined that the PC5 control plane integrity protection of the second PC5 link is activated, and When it is determined that the PC5 control plane confidentiality protection of the second PC5 link needs to be activated, a non-empty PC5 control plane confidentiality protection algorithm and a non-empty PC5 control plane integrity protection algorithm need to be selected; If the PC5 control plane integrity protection of the road is not activated, it is not necessary to select the PC5 control plane integrity wave protection algorithm.
  • the second terminal device selects the 128-bit algorithm or the 256-bit algorithm according to the security algorithm policy.
  • the specific selection method please refer to the description in 5.3.3.1.4.3 of the standard TS33.536 chapter.
  • Step 406 the second terminal device sends the PC5 control plane security algorithm of the second PC5 link to the first relay.
  • the second terminal device activates the security protection method determined in step 405. Specifically, if the PC5 control plane integrity protection is enabled, the integrity protection of the message in step 406 is started using the PC5 control plane integrity protection algorithm and the PC5 control plane integrity protection key. If the PC5 Control Plane Confidentiality Protection is determined to be ON, start preparing to decrypt the received message using the selected PC5 Control Plane Confidentiality Protection Algorithm and PC5 Control Plane Confidentiality Key.
  • the PC5 control plane algorithm and PC5 control plane key may refer to the relevant control plane algorithm and control plane key mentioned in Section 5.3.3.1.4.3 of the standard TS 33.536.
  • the method for determining the PC5 control plane security algorithm is: the second terminal device stores a control plane integrity protection algorithm priority list, and the second terminal device can obtain support from the first terminal device and/or the first relay carried in step 402 Among the control plane security algorithms, select a control plane security algorithm with the highest priority that is supported at the same time. For example, if the first terminal device supports NIA0 (Nextgeneration Integrity Algorithm, the next generation integrity protection algorithm), NIA1, NIA2, NIA3 the first relay supports NIA0, NIA2, NIA3 The priority list of the second terminal device is NIA1, NIA3, NIA2. In the case where only the first terminal device and the second terminal device are considered, the selected control plane integrity protection algorithm is NIA1.
  • NIA0 Nextgeneration Integrity Algorithm, the next generation integrity protection algorithm
  • the selected control plane integrity protection algorithm is NIA3.
  • the selected control plane integrity protection algorithm is NIA2.
  • the selected control plane integrity protection algorithm is NIA2.
  • the selected control plane integrity protection algorithm is NEA1.
  • the selected control plane integrity protection algorithm is NEA3.
  • the selected control plane integrity protection algorithm is NEA2.
  • the second terminal device sends a direct security mode signaling (direct security mode command, DSMC) message to the first relay, where the message carries the control plane security algorithm used by the second terminal device to determine the second PC5 link.
  • DSMC direct security mode command
  • Step 407 the first relay activates the control plane security of the second PC5 link according to the received control plane security algorithm of the second PC5 link. Specifically, the first relay activates the control plane security protection of the second PC5 link according to the PC5 control plane algorithm carried in step 406 .
  • the specific activation method please refer to the description in 5.3.3.1.4.3 of the standard TS33.536 chapter.
  • control plane security algorithm of the second PC5 link includes a non-null integrity protection algorithm and a null confidentiality protection algorithm
  • the first relay enables the control plane integrity protection of the second PC5 link
  • the control plane confidentiality protection of the second PC5 link is not enabled.
  • specific activation method please refer to the description in 5.3.3.1.4.3 of the standard TS33.536 chapter.
  • Step 408 the first relay performs an authentication process with the first terminal device.
  • the first relay sends a Direct Auth and Key Establishment message to the first terminal device, and initiates an authentication and key generation process.
  • a Direct Auth and Key Establishment message to the first terminal device, and initiates an authentication and key generation process.
  • the first relay needs to determine whether the control plane security policy of the first terminal device can be collided by the first relay. The relay performs the following steps. Otherwise, release the connection. If the first relay has already made a judgment in step 402, it is not necessary to perform this judgment process again.
  • Step 409 the first relay determines the PC5 control plane security algorithm of the first PC5 link, and activates the control plane security of the first PC5 link.
  • the first PC5 link refers to the PC5 link between the first terminal device and the first relay.
  • the first relay may use the control plane security protection method between the first relay and the second terminal device as the PC5 control plane security protection method of the first PC5 link. Specifically, the first relay may use the decision result on the first PC5 link according to the decision result in step 407 .
  • the first relay may determine the control plane security protection method between the first terminal device and the first relay by itself, as the PC5 control plane security protection method of the first PC5 link.
  • the security protection method may be the same as or different from the control plane security protection method between the first relay and the second terminal device. That is, the first link and the second link are independent of each other.
  • the first relay checks whether the control plane security protection method is compatible with the PC5 control plane of the first terminal device. If the security policy conflicts, the connection is released if there is a conflict, and if there is no conflict, the control plane security protection method between the first relay and the second terminal device is determined as the PC5 control plane security protection method of the first PC5 link.
  • the first relay selects the PC5 control plane security algorithm of the first PC5 link, and activates the control plane security of the first PC5 link.
  • the first relay can determine whether the control plane security algorithm selected by the second terminal device can be used directly, and if it can be used directly, the second terminal device is used as the PC5 control plane security algorithm of the first PC5 link. If not, make another algorithm selection.
  • the further determination method mainly depends on whether the algorithm selected by the second terminal device has the highest priority supported by the first relay, and if so, it is determined that it can be used.
  • the first relay should select the security algorithm (a confidentiality protection algorithm and/or an integrity protection algorithm) supported by UE-1 and at the same time the first relay has the highest priority. In the second way, the first relay determines the security algorithm of the first PC5 link according to the description in step 406 .
  • the security algorithm a confidentiality protection algorithm and/or an integrity protection algorithm
  • Step 410 the first relay sends the control plane security algorithm of the first PC5 link to the first terminal device.
  • the first relay activates the control plane security protection between the first terminal device and the first relay.
  • the activation method can refer to step 406 .
  • the first relay sends a Direct Security Mode Command message to the first terminal device, where the message carries the control plane security algorithm of the first PC5 link.
  • Step 411 the first terminal device activates the PC5 control plane security of the first PC5 link according to the received control plane security algorithm.
  • the above steps 401 to 411 are the process of determining the control plane security protection method of the PC5 link between the terminal devices.
  • the control planes of the first PC5 link and the second PC5 link can be guaranteed
  • the consistency of security can realize the coordinated processing of the control plane security protection on both sides of the relay, so that the links on both sides of the relay can either activate the control plane integrity protection method or not activate the control plane integrity protection method.
  • and/or make the links on both sides of the relay either activate the control plane confidentiality protection method, or neither activate the control plane confidentiality protection method, so that the links on both sides of the relay keep the security protection processing method Consistent.
  • the following steps 412 to 419 are the process of determining the user plane security protection method of the PC5 link between the terminal devices.
  • Step 412 the first terminal device sends the DSMP message of the first PC5 link to the first relay.
  • the first terminal device replies a direct security mode signaling (direct security mode command, DSMC) message to the first relay, and the DSMP message is used to respond to the Direct Security Mode Command message, which can carry the first The PC5 user plane security policy of the terminal device.
  • direct security mode command direct security mode command
  • Step 413 the first relay sends the DSMP message of the second PC5 link to the second terminal device.
  • the DSMP message of the second PC5 link may also carry the PC5 user plane security policy of the first relay, or the first relay may also send the PC5 user plane security policy of the first relay to the second terminal device.
  • the DSMP message of the second PC5 link carries the PC5 user plane security policy of the first terminal and the PC5 user plane security policy of the first relay.
  • the second PC5 link DSMP message may also be a new DSMP message sent by the first relay, and the new DSMP message carries the PC5 user plane security policy of the first relay.
  • the first relay replaces the PC5 user plane security policy of the first terminal device in the DSMP message of the first PC5 link with the PC5 user plane security policy of the first relay.
  • Step 414 the second terminal device determines the PC5 user plane security protection method of the second PC5 link according to the PC5 user plane security policy from the first relay and the PC5 user plane security policy of the second terminal device, and determines the second PC5 user plane security protection method.
  • the PC5 user plane security algorithm of the link is the PC5 user plane security algorithm of the link.
  • the second terminal device may determine whether to activate the PC5 user plane security protection method of the second PC5 link in at least one of the following manners:
  • the second terminal device determines whether to activate the PC5 user plane security protection method of the second PC5 link according to the PC5 user plane security policy of the first relay and the PC5 user plane security policy of the second terminal device.
  • the specific carrying method please refer to the description in 5.3.3.1.4.2 of the standard TS33.536 chapter.
  • the second terminal device determines whether to activate the second PC5 in addition to the PC5 user plane security policy of the first relay and the PC5 user plane security policy of the second terminal device in combination with the PC5 user plane security policy of the first terminal device
  • the security protection method of the PC5 user plane of the link In this way, the PC5 user plane security protection method between the first relay and the second terminal device is the same as the PC5 user plane security protection method between the first relay and the first terminal device.
  • any two user plane confidentiality protection policies and/or user plane integrity protection policies conflict one is NOT NEEDED, the other is REQUIRED
  • the second terminal device releases the connection.
  • the security corresponding to REQUIRED is enabled.
  • the user plane confidentiality policy of the first terminal device is REQUIRED, or the user plane confidentiality protection policy of the second terminal device is REQUIRED, the second terminal device enables user plane confidentiality protection.
  • the second terminal device can determine the user plane confidentiality Confidentiality protection is enabled, or it can be determined that user plane confidentiality protection is not enabled. When there is no conflict between any two user plane confidentiality protection policies and/or user plane integrity protection policies, if there is NOT NEEDED, the corresponding security will not be enabled. For example, if the user plane confidentiality policy of the first terminal device is NOT NEEDED, or the user plane confidentiality protection policy of the second terminal device is NOT NEEDED, the second terminal device does not enable user plane confidentiality protection.
  • the method for enabling the security of the user plane may refer to the activated security protection method of the second PC5 link control plane. Specifically, if the control plane confidentiality protection is enabled, the user plane confidentiality protection may or may not be enabled. If the control plane confidentiality protection is not enabled, the user plane confidentiality protection is disabled. If the control plane integrity protection is enabled, the user plane integrity protection may or may not be enabled. If the control plane integrity protection is not enabled, the user plane integrity protection is disabled.
  • the second terminal device may determine the PC5 user plane security algorithm.
  • a possible implementation manner is to reuse the selected PC5 control plane security algorithm as the PC5 user plane security algorithm.
  • Another implementation method is to reselect the PC5 user plane security algorithm.
  • the security algorithm includes a confidentiality protection algorithm and/or an integrity protection algorithm.
  • the second terminal device selects the 128-bit algorithm or the 256-bit algorithm according to the security algorithm policy.
  • Step 415 the second terminal device sends the first information to the first relay.
  • the first information is used to indicate the user plane security protection method of the second PC5 link.
  • the first information is the user plane security activation indication of the second PC5 link.
  • the second terminal device sends a direct communication accept message to the first relay.
  • the message carries the user plane security activation indication of the second PC5 link.
  • the definition of the user plane security activation indication can refer to the description in 5.3.3.1.4.2 of the standard TS33.536 chapter.
  • the user plane security protection method of the second PC5 link determined by the second terminal device is that the user plane confidentiality protection of the second PC5 link is disabled, and the user plane integrity protection of the second PC5 link is enabled. Then, the user plane security activation instruction is used to instruct to activate the user plane integrity protection of the second PC5 link, and not to activate the user plane confidentiality protection of the second PC5 link.
  • Step 416 the first relay activates the user plane security protection of the second PC5 link according to the first information.
  • the first relay after the first relay receives the user plane security activation instruction, it activates the first relay and activates the user plane integrity protection of the second PC5 link according to the user name security activation instruction, and does not activate the first relay to activate the second relay.
  • User plane confidentiality protection for PC5 links After the first relay receives the user plane security activation instruction, it activates the first relay and activates the user plane integrity protection of the second PC5 link according to the user name security activation instruction, and does not activate the first relay to activate the second relay.
  • Step 417 the first relay sends the second information to the first terminal device.
  • the second information is used to indicate a user plane security protection method of the first PC5 link.
  • the second information is the first information, that is, the first relay forwards the first information to the first terminal device.
  • the first relay determines the PC5 user plane security protection method of the first PC5 link according to the user plane security protection method of the second PC5 link, and generates second information, the second information and the first information is the same.
  • the first relay determines that the PC5 user plane security protection method of the first PC5 link is also to enable user plane integrity protection, but not to enable user plane confidentiality protection.
  • Step 418 the first terminal device activates the user plane security of the first PC5 link according to the second information.
  • the first terminal device activates the user plane integrity protection of the first PC5 link, and the first PC5 link The user plane confidentiality protection of the road is disabled.
  • control plane security protection determination process shown in the above steps 401 to 411 and the user plane security protection determination process shown in steps 412 to 419 may be decoupled, that is, they may be executed separately.
  • the first relay does not have the PC5 control plane security protection of the first PC5 link determined by the second terminal device when the first relay activates the PC5 control plane security protection method of the first PC5 link
  • the first relay needs to determine whether it can support the user plane security protection method of the second PC5 link determined by the second terminal device before determining the user plane security protection method of the first PC5 link. If it is supported, it does not meet the requirement that the user plane security protection method is consistent, then the first relay needs to release the connection, and the establishment of the direct communication link fails.
  • FIG. 5 is a schematic flowchart of a secure communication method provided by an embodiment of the present application. The method is still executed by the first communication device, and the method may include the following steps.
  • Step 501 the first terminal device broadcasts a first direct communication request (direct communication request, DCR) message.
  • step 401 For details, refer to step 401 above.
  • Step 502 after receiving the first DCR message, at least one relay sends a second DCR message to the second terminal device.
  • step 402 For details, refer to step 402 above.
  • Step 503 the second terminal device determines the first relay for establishing the second PC5 link from at least one relay.
  • the first DCR message includes that the security endpoint policy of the first terminal device is "end-to-end" security, then hereinafter in this embodiment, it is determined according to the second terminal device that the security endpoint is located in the first terminal device. A terminal device is discussed.
  • Step 504a after the second terminal device determines the first relay, initiates an authentication process with the first relay.
  • the message sent by the second terminal includes indication information, and the indication information is used to indicate that authentication and key distribution are performed between the second terminal device and the first terminal device. For details, see step 404 above.
  • Step 504b the first relay initiates an authentication process to the first terminal device.
  • the first relay receives the security endpoint from the second terminal device. After the message is not parsed, it is directly sent to the first terminal device, which has the advantage of reducing the communication delay.
  • step 404 For the method of identifying the End-to-End by the first relay, reference may be made to the relevant description of step 404 .
  • Step 505 the second terminal device determines the PC5 control plane security protection method of the PC5 link between the first terminal device and the second terminal device, and selects the PC5 between the first terminal device and the second terminal device The PC5 control plane security algorithm for the link.
  • the second terminal device determines the PC5 control plane security protection of the PC5 link between the first terminal device and the first terminal device according to the control plane security policy of the first terminal device and the control plane security policy of the second terminal device method.
  • the PC5 control plane integrity protection of the first terminal device is REQUIRED
  • the PC5 control plane confidentiality protection of the first terminal device is REQUIRED
  • the PC5 control plane integrity protection of the second terminal device is REQUIRED
  • the second terminal device's PC5 control plane integrity protection is REQUIRED.
  • the PC5 control plane confidentiality protection is NOT NEEDED, then the second terminal device determines to enable the PC5 control plane security integrity protection of the PC5 link between the first terminal device and the second terminal device, and does not enable the first terminal device and the second terminal device.
  • the second terminal device may further base on the user plane security policy of the first terminal device and the user plane security policy of the second terminal device, and the control plane security algorithm of the first terminal device and the second terminal
  • the control plane security algorithm of the device determines the PC5 control plane security algorithm of the PC5 link between the first terminal device and the first terminal device.
  • Step 506 the second terminal device sends the selected PC5 control plane security algorithm to the first terminal device.
  • the PC5 control plane security algorithm is used for the first terminal device and the second terminal device to protect the PC5 link between the first terminal device and the second terminal device.
  • the second terminal device sends a direct security mode signaling (direct security mode command, DSMC) message to the first terminal device, where the message carries a control plane security algorithm for the second terminal device to determine the second PC5 link .
  • DSMC direct security mode command
  • Step 507 the first terminal device activates the PC5 control plane security of the PC5 link between the first terminal device and the second terminal device according to the received control plane security algorithm of the PC5 link.
  • the above steps 501 to 508 are the process of determining the control plane security protection method of the PC5 link between the terminal devices.
  • the PC5 link between the first terminal device and the second terminal device can be determined.
  • the control plane security protection method can realize the consistency in the processing method of control plane security protection for each device.
  • the following steps 508 to 511 are the process of determining the user plane security protection method of the PC5 link between the terminal devices.
  • Step 508 the first terminal device sends the first DSMP message to the second terminal device.
  • the first terminal device sends a first direct security mode signaling (direct security mode complete, DSMP) message to the second terminal device, where the first DSMP message is used to respond to the Direct Security Mode Command message, in which The PC5 user plane security policy of the first terminal device can be carried.
  • DSMP direct security mode complete
  • Step 509 the second terminal device determines the PC5 user of the PC5 link between the first terminal device and the second terminal device according to the PC5 user plane security policy from the first terminal device and the PC5 user plane security policy of the second terminal device. face security method.
  • the second terminal device determines the PC5 user plane security protection of the PC5 link between the first terminal device and the first terminal device according to the user plane security policy of the first terminal device and the user plane security policy of the second terminal device method.
  • the PC5 user plane integrity protection of the first terminal device is REQUIRED
  • the PC5 user plane confidentiality protection of the first terminal device is REQUIRED
  • the PC5 user plane integrity protection of the second terminal device is REQUIRED-
  • the second terminal device The PC5 user plane confidentiality protection is NOT NEEDED, then the second terminal device determines to open the PC5 user plane security integrity protection of the PC5 link between the first terminal device and the second terminal device, and does not open the first terminal device and the second terminal device.
  • PC5 user plane security confidentiality protection of the PC5 link between two terminal devices is NOT NEEDED
  • the second terminal device may select the PC5 user plane security algorithm.
  • the security algorithm includes a confidentiality protection algorithm and/or an integrity protection algorithm.
  • the second terminal device selects the 128-bit algorithm or the 256-bit algorithm according to the security algorithm policy.
  • Step 510 the second terminal device sends third information to the first terminal device.
  • the third information includes user plane security activation indication information of the PC5 link between the first terminal device and the second terminal device.
  • the user plane security activation indication information is used to indicate the user plane security protection method of the PC5 link between the first terminal device and the second terminal device.
  • the second terminal device sends a direct communication accept message to the first terminal device.
  • the message carries the user plane security activation indication.
  • Step 511 the first terminal device determines the user plane security protection method of the PC5 link between the first terminal device and the second terminal device, and activates the user plane security of the PC5 link between the first terminal device and the second terminal .
  • the above steps 509 to 512 are the process of determining the user plane security protection method of the PC5 link between the terminal devices.
  • the PC5 link between the first terminal device and the second terminal device can be determined
  • the user-plane security protection method based on the method can realize the consistency in the processing method of the user-plane security protection of each device.
  • FIG. 6 is a schematic flowchart of a secure communication method provided by an embodiment of the present application, and the method may include the following steps.
  • Step 601 the first terminal device broadcasts a direct communication request (direct communication request, DCR).
  • step 401 For details, refer to step 401 above.
  • this embodiment adopts hop-by-hop security, so the location of the security termination point is located in the relay, and the following description of this embodiment is based on the case where the location of the security termination point is located in the relay.
  • each relay that receives the DCR message determines a security protection method for the PC5 control plane of the first PC5 link according to the PC5 control plane security policy of the first terminal device and the PC5 control plane security policy of the relay itself.
  • the integrity protection of the PC5 control plane of the first terminal device and the relay is REQUIRED, it is determined to enable the integrity protection of the PC5 control plane. If the PC5 control plane integrity protection of the first terminal device and the relay has NOT NEEDED, it is determined that the PC5 control integrity protection is not enabled. If the confidentiality protection of the PC5 control plane of the first terminal device and the relay is REQUIRED, it is determined that the confidentiality protection of the PC5 control plane is enabled. If the confidentiality protection of the PC5 control plane of the first terminal device and the relay has NOT NEEDED, it is determined that the confidentiality protection of the PC5 control plane is not enabled.
  • PC5 control plane integrity protection of the first terminal device and the relay are both PREFERRED, it may be determined to enable the PC5 control plane integrity protection, or it may be determined not to enable the control plane integrity protection. If both the PC5 control plane confidentiality protection of the first terminal device and the relay are PREFERRED, it may be determined to enable the PC5 control plane confidentiality protection, or it may be determined not to enable the control plane confidentiality protection.
  • each relay may determine the security protection method for the PC5 control plane of the first PC5 link according to the foregoing step 406 .
  • Step 602b each relay that receives the first DCR message sends a second DCR message to the second terminal device, wherein the second DCR message includes the first PC5 link PC5 control plane security protection method determined by itself .
  • the PC5 control plane security protection method of the first PC5 link determined by each relay itself can be given the format of the security policy, and then each relay can use the first PC5 link determined by itself.
  • the PC5 control plane security protection method of the present invention replaces the PC5 control plane security policy of the first terminal device in the DCR message. Specifically, if it is determined that the control plane integrity protection is enabled, the PC5 control plane security policy whose control plane integrity protection is REQUIRED is transmitted, and if the control plane integrity protection is not enabled, the PC5 control plane whose control plane integrity protection is NOT NEEDED is transmitted. face security policy. If it is determined that the control plane confidentiality protection is enabled, the PC5 control plane security policy whose control plane confidentiality protection is REQUIRED is passed.
  • the PC5 control plane security policy whose control plane confidentiality protection is NOT NEEDED is passed. .
  • what the first terminal device carries in the first DCR message is that the PC5 control plane confidentiality protection is in the "PREFERRED” state, and the PC5 control plane integrity protection is in the "PREFERRED” state.
  • the first relay determines that the control plane integrity protection of the second PC5 link is in the "REQUIRED” state, and the control plane confidentiality is protected. to "REQUIRED” state. Then, the first relay can replace the PC5 control plane security policy of the first terminal device in the second DCR message with the control plane confidentiality protection being "REQUIRED” state, and the control plane integrity protection being "REQUIRED” state.
  • the DCR message sent by each relay further includes an indication message, where the indication information is used to indicate that the location of the security termination point is located in the relay.
  • the PC5 control plane security protection method of the first PC5 link determined by each relay itself may be given an indication information format or a string format. For example, "00" indicates that the control plane confidentiality protection is not enabled, and the control plane integrity protection is not enabled, "01" indicates that the control plane confidentiality protection is not enabled, and the control plane integrity protection is enabled; or “enabled, enabled” indicates information. For example, passing “enabled, disabled” means enabling the control plane integrity protection. If the control plane confidentiality protection is not enabled, the second terminal device can determine the relay selected or the second terminal device itself can use the received DCR message according to the received DCR message. PC5 Control Plane Security Policy.
  • the second DCR message may carry at least one PC5 security algorithm policy as in step 402 while carrying the PC5 control plane security protection method of the first PC5 link determined by itself.
  • Step 603 the second terminal device selects a relay serving the first terminal from at least one relay.
  • this step 403 is an optional step.
  • the second terminal device only needs to judge whether the relay supports the service, and if so, determine that the relay is a relay served by the first terminal. For example, the second terminal device determines whether it is interested in the application information carried in the message.
  • the second terminal device determines, according to the received PC5 control plane security protection method of the first PC5 link, The second terminal device supports the control plane security protection method of which relay the determined first PC5 link, and the second terminal device selects one relay as the target relay, for example, selects the first relay as the target relay.
  • steps 604 to 611 are the same as the above-mentioned steps 404 to 411, and are not repeated here.
  • step 605 the PC5 control plane security protection method of the first PC5 link and the PC5 control plane security protection policy of the second terminal device according to the second terminal device carried in step 602b and determined by the relay itself , and determine the PC5 control plane security protection method of the second PC5 link. Specifically, if it is delivered in the form of a security policy, the second terminal device determines the PC5 control plane security protection method of the second PC5 link according to the security policy carried in the second DCR message. If it is delivered in the form of indication information, the second terminal device determines the PC5 control plane security policy of the second PC5 link according to the indication information.
  • the second terminal device determines the security policy of the second PC5 link, before sending step 606, activate the PC5 control plane security of the second PC5 link.
  • the above steps 601 to 611 are the process of determining the security protection method for the control plane of the PC5 link between the terminal devices.
  • the control planes of the first PC5 link and the second PC5 link can be guaranteed
  • the consistency of security can realize the coordinated processing of the control plane security protection on both sides of the relay, so that the links on both sides of the relay can either activate the control plane integrity protection method or not activate the control plane integrity protection method.
  • and/or make the links on both sides of the relay either activate the control plane confidentiality protection method, or neither activate the control plane confidentiality protection method, so that the links on both sides of the relay keep the security protection processing method Consistent.
  • the following steps 612 to 618 are the process of determining the security of the user plane of the PC5 link between the terminal devices.
  • Step 612 the first terminal device sends the DSMP message of the first PC5 link to the first relay.
  • the first terminal device replies a direct security mode signaling (direct security mode complete, DSMP) message to the first relay, where the DSMP message is used to respond to the Direct Security Mode Command message, and the message may carry the first The PC5 user plane security policy of the terminal device.
  • DSMP direct security mode complete
  • Step 613 the first relay determines a security protection method for the PC5 user plane of the first PC5 link according to the PC5 user plane security policy of the first terminal device and the PC5 user plane security policy of the first relay itself.
  • Step 614 the first relay sends a DSMP message of the second PC5 link, where the message includes the PC5 user plane security protection method of the first PC5 link determined by the first relay.
  • the delivery method of the user plane security protection method reference may be made to the relevant description of step 602b.
  • Step 615 the second terminal device determines the PC5 user plane security protection method of the second PC5 link.
  • the second terminal device determines the PC5 user plane security protection method of the second PC5 link according to the PC5 user plane security protection method of the first PC5 link determined by the relay itself and the PC5 user plane security policy of the second terminal device. Specifically, if it is transmitted in the form of a security policy, the second terminal device determines the PC5 user plane security protection method of the second PC5 link according to the security policy carried in the second DCR message. If it is delivered in the form of indication information, the second terminal device determines the PC5 user plane security protection method of the second PC5 link according to the indication information.
  • Steps 617 to 619 are the same as the above-mentioned steps 417 to 419, and are not repeated here.
  • the relay determines the control plane security and the user plane security of the PC5 link between the first terminal device and the second terminal device. According to the above method, the consistency of the control plane/user plane security of the PC5 link between the first terminal device and the second terminal device can be ensured, and the coordinated processing of the control plane/user plane security protection on both sides of the relay can be realized.
  • Make the links on both sides of the relay either activate the control plane/user plane integrity protection method, or neither activate the control plane/user plane integrity protection method, and/or make the links on both sides of the relay either activate Control plane/user plane confidentiality protection method, or do not activate the control plane/user plane confidentiality protection method, so that the links on both sides of the relay maintain the same security protection processing method.
  • step numbers of the flowcharts described in the embodiments of the present application are only an example of the execution flow, and do not constitute a restriction on the sequence of steps performed. There is no strict order of execution.
  • the secure communication method provided by the embodiments of the present application has been introduced from the perspective of the terminal as an execution subject.
  • the terminal may include a hardware structure and/or a software module, and implement the above functions in the form of a hardware structure, a software module, or a hardware structure plus a software module. Whether one of the above functions is performed in the form of a hardware structure, a software module, or a hardware structure plus a software module depends on the specific application and design constraints of the technical solution.
  • the embodiments of the present application further provide a communication apparatus 700, where the communication apparatus 700 is used to implement the functions of the first terminal device, the second terminal device and the relay in the above method.
  • the first communication apparatus 700 may be a first terminal device, or may be a device in the first terminal device.
  • the apparatus may be a system-on-a-chip.
  • the chip system may be composed of chips, or may include chips and other discrete devices.
  • the communication apparatus 700 includes a processing unit 701 and a transceiver unit 702 .
  • the communication apparatus 700 is used to realize the function of the second terminal device in the above-mentioned method:
  • the transceiver unit 702 is configured to receive a first request message about the first terminal device from the relay; the first request message includes the PC5 user plane security policy of the first terminal device and the PC5 user plane security of the relay Strategy.
  • a processing unit 701 configured to determine the first information according to the PC5 user plane security policy of the second terminal device, the PC5 user plane security policy of the first terminal device, and the relayed PC5 user plane security policy;
  • the transceiver unit 702 is further configured to send the first information to the relay, where the first information is used to indicate the user plane security protection method of the first PC5 link and the user plane security of the second PC5 link Protection method; wherein, the user plane security protection method of the first PC5 link is the same as the user plane security protection method of the second PC5 link;
  • the first PC5 link is the PC5 link between the relay and the first terminal device;
  • the second PC5 link is the link between the relay and the second terminal device PC5 link.
  • the first information is used to indicate the user plane security protection method of the first PC5 link and the user plane security protection method of the second PC5 link, including:
  • the first information is used to indicate: the user plane integrity protection of the first PC5 link and the user plane integrity protection of the second PC5 link are both enabled or disabled, and/or, the first The user plane confidentiality protection of one PC5 link and the user plane confidentiality protection of the second PC5 link are both enabled or disabled.
  • the transceiver unit 702 is further configured to receive a second request message about the first terminal device from the relay, where the second request message includes the PC5 control of the first terminal device The PC5 control plane security policy of the relay described in the plane security policy;
  • the processing unit 701 is further configured to determine the second terminal device according to the PC5 control plane security policy of the second terminal device, the PC5 control plane security policy of the first terminal device, and the relay PC5 control plane security policy. Control plane security algorithm of PC5 link;
  • the transceiver unit 702 is further configured to send the control plane security algorithm of the second PC5 link to the relay, where the control plane security algorithm is used to indicate the control plane security and all parameters of the second PC5 link.
  • the control plane security of the first PC5 link wherein the control plane security protection method of the first PC5 link is the same as the control plane security protection method activated on the second PC5 link.
  • the second request message further includes a security termination policy indication, where the security termination policy indication is used to indicate that the security termination point is located on the relay.
  • control plane security algorithm is used to instruct the control plane security protection method of the second PC5 link and the control plane security protection method of the first PC5 link, including
  • the control plane security algorithm is used to indicate: the control plane integrity protection of the first PC5 link and the control plane integrity protection of the second PC5 link are both enabled or not enabled, and/or, the Both the control plane confidentiality protection of the first PC5 link and the control plane confidentiality protection of the second PC5 link are enabled or disabled.
  • the processing unit 701 determines, according to the PC5 user plane security policy of the second terminal device, the PC5 user plane security policy of the first terminal device, and the PC5 user plane security policy of the relay
  • the first information is specifically used for:
  • the PC5 user plane security policy of the second terminal device the PC5 user plane security policy of the first terminal device, the PC5 user plane security policy of the relay, and the control plane security of the second PC5 link an algorithm to determine the first information;
  • the security level of the user plane security protection method of the second PC5 link is not higher than the security level of the control plane security protection method of the second PC5 link, and the user plane security protection level of the first PC5 link
  • the security level of the method is not higher than the security level of the control plane security protection method of the first PC5 link.
  • the user plane security protection method of the second PC5 link is not higher than the control plane security protection method of the second PC5 link
  • the user plane security protection method of the first PC5 link is A control plane security protection method with a security level not higher than the first PC5 link, including:
  • control plane confidentiality protection of the third PC5 link When the control plane confidentiality protection of the third PC5 link is enabled, the user plane confidentiality protection of the third PC5 link is enabled or disabled;
  • control plane integrity protection of the third PC5 link When the control plane integrity protection of the third PC5 link is enabled, the user plane integrity protection of the third PC5 link is enabled or disabled;
  • the third PC5 link is the second PC5 link or the first PC5 link.
  • processing unit 701 and the transceiver unit 702 For the specific execution process and beneficial effects of the processing unit 701 and the transceiver unit 702, reference may be made to the description in the method embodiment shown in FIG. 4 above.
  • the communication apparatus 700 is configured to implement the function of the second terminal device in the above method:
  • the transceiver unit 702 is configured to request an indication including a security termination point policy, and the indication of the security termination point policy is used to indicate that the security termination point is located on the relay;
  • a transceiver unit 702 configured to receive the PC5 control plane security protection method of the first PC5 link and the PC5 control plane security protection method of the second PC5 link determined by the at least one relay;
  • a processing unit 701, configured to use the PC5 control plane security policy of the second terminal device, and the PC5 control plane security protection method of the first PC5 link and the PC5 link of the second PC5 link determined by the at least one relay Control plane security protection method to determine target relay;
  • the transceiver unit 702 is further configured to receive the PC5 user plane security protection method of the first PC5 link and the PC5 user plane security protection method of the second PC5 link determined by the target relay;
  • the processing unit 701 is further configured to determine the first information according to the PC5 user plane security protection repetition of the first PC5 link from the target relay and the PC user plane security protection method of the second terminal device;
  • the transceiver unit 702 is further configured for the second terminal device to send the first information to the relay, where the first information is used to indicate the user plane security protection method of the first PC5 link and the second PC5 The user plane security protection method of the link; wherein, the user plane security protection method of the first PC5 link is the same as the user plane security protection method of the second PC5 link;
  • the first PC5 link is the PC5 link between the relay and the first terminal device;
  • the second PC5 link is the link between the relay and the second terminal device PC5 link.
  • the first information is used to indicate the user plane security protection method of the first PC5 link and the user plane security protection method of the second PC5 link, including:
  • the first information is used to indicate: the user plane integrity protection of the first PC5 link and the user plane integrity protection of the second PC5 link are both enabled or disabled, and/or, the first The user plane confidentiality protection of one PC5 link and the user plane confidentiality protection of the second PC5 link are both enabled or disabled.
  • the processing unit is further configured to, according to the PC5 user plane security protection method of the first PC5 link and the PC5 user plane security protection method of the second PC5 link determined from the target relay, determining the control plane security algorithm of the second PC5 link,;
  • the transceiver unit 702 is further configured to send the control plane security algorithm of the second PC5 link to the relay, where the control plane security algorithm of the second PC5 link is used to indicate the control of the second PC5 link plane security and control plane security of the first PC5 link.
  • control plane security algorithm of the second PC5 link is used to indicate the control plane security of the second PC5 link and the control plane security of the first PC5 link, including:
  • the control plane security algorithm of the second PC5 link is used to indicate that both the control plane integrity protection of the first PC5 link and the control plane integrity protection of the second PC5 link are enabled or disabled, And/or, both the control plane confidentiality protection of the first PC5 link and the control plane confidentiality protection of the second PC5 link are enabled or disabled.
  • the processing unit 701 determines the first information according to the PC5 user plane security protection method of the first PC5 link from the target relay and the PC user plane security policy of the second terminal device , specifically for:
  • the security level of the user plane security protection method of the second PC5 link is not higher than the security level of the control plane security protection method of the second PC5 link, and the user plane security protection level of the first PC5 link
  • the security level of the method is not higher than the security level of the control plane security protection method of the first PC5 link.
  • the user plane security protection method of the second PC5 link is not higher than the control plane security of the second PC5 link, and the security level of the user plane security protection method of the first PC5 link A control plane security protection method no higher than the first PC5 link, including:
  • control plane confidentiality protection of the third PC5 link When the control plane confidentiality protection of the third PC5 link is enabled, the user plane confidentiality protection of the third PC5 link is enabled or disabled;
  • control plane integrity protection of the third PC5 link When the control plane integrity protection of the third PC5 link is enabled, the user plane integrity protection of the third PC5 link is enabled or disabled;
  • the third PC5 link is the second PC5 link or the first PC5 link.
  • processing unit 701 and the transceiver unit 702 For the specific execution process and beneficial effects of the processing unit 701 and the transceiver unit 702, reference may be made to the description in the method embodiment shown in FIG. 6 above.
  • the communication apparatus 700 is used to realize the function of the second terminal device in the above-mentioned method:
  • a transceiver unit 702 configured to receive a direct connection communication request from the first terminal device through at least one relay;
  • a processing unit 701 configured to determine a target relay from the at least one relay according to the security policy assistance information
  • the transceiver unit 701 is configured to communicate with the first terminal device through the target relay.
  • the security policy assistance information includes a PC control plane security policy of the at least one relay
  • the processing unit 701 determines the target relay from the at least one relay, and is specifically used for:
  • a target relay including an optional PC5 control plane security policy is selected from the at least one relay.
  • the security policy auxiliary information includes a PC control plane security policy of the at least one relay, and a PC5 control plane security policy of the second terminal device;
  • the second terminal device determines the target relay from the at least one relay according to the security policy assistance information, including:
  • the processing unit 701 is specifically configured to select a target relay whose PC control plane security policy of the relay does not conflict with the PC5 control plane security policy of the second terminal device according to the at least one relay.
  • the security policy auxiliary information includes a PC control plane security policy of the at least one relay, and a PC5 control plane security policy of the second terminal device;
  • the processing unit 701 is specifically configured for the second terminal device to select one relay from the at least one relay according to the security policy auxiliary information, and the security level of the PC user plane security protection method is not higher than that of the first relay.
  • the target relay of the security level of the PC control plane security protection method of the second terminal device is specifically configured for the second terminal device to select one relay from the at least one relay according to the security policy auxiliary information, and the security level of the PC user plane security protection method is not higher than that of the first relay.
  • the target relay of the security level of the PC control plane security protection method of the second terminal device is specifically configured for the second terminal device to select one relay from the at least one relay according to the security policy auxiliary information, and the security level of the PC user plane security protection method is not higher than that of the first relay.
  • the security policy auxiliary information is pre-configured by the policy control function network element.
  • processing unit 701 and the transceiver unit 702 For the specific execution process and beneficial effects of the processing unit 701 and the transceiver unit 702, reference may be made to the description in the method embodiment shown in FIG. 6 above.
  • the communication device 700 is used to implement the relay function in the above method:
  • a transceiver unit 702 configured to send a first request message about the first terminal device to the second terminal device; the first request message includes the PC5 user plane security policy of the first terminal device and the relayed PC5 user face security policy;
  • a transceiver unit 702 configured to receive first information from the second terminal device, where the first information is used to indicate the user plane security protection method of the first PC5 link and the user plane security protection method of the second PC5 link; wherein , the user plane security protection method of the first PC5 link is the same as the user plane security protection method of the second PC5 link;
  • a processing unit 701 configured to activate the user plane security protection method of the second PC5 link and activate the user plane security protection method of the first PC5 link according to the first information
  • the first PC5 link is the PC5 link between the relay and the first terminal device
  • the second PC5 link is the PC5 link between the relay and the second terminal device road.
  • the transceiver unit 702 is further configured to send the control plane security policy of the first terminal device and the control plane security policy of the relay to the second terminal device.
  • the control plane security policy and the control plane security policy of the relay are used to determine the control plane security algorithm of the second PC5 link;
  • the transceiver unit 702 is further configured to receive the control plane security algorithm of the second PC5 link from the second terminal device, where the control plane security algorithm is used to indicate the control plane security protection of the second PC5 link A method and a control plane security protection method for the first PC5 link;
  • the processing unit 701 is further configured to activate the control plane security protection method of the second PC5 link and the control plane security of the first PC5 link according to the control plane security algorithm of the second PC5 link A protection method, wherein the control plane security protection method of the first PC5 link is the same as the control plane security protection method activated on the second PC5 link.
  • the security level of the PC5 control plane security protection method of the relay is not higher than the security level of the PC5 user plane security protection method of the second link.
  • the security level of the user plane security protection method of the first PC5 link is not higher than the security level of the control plane security protection method of the first PC5 link;
  • the security level of the security protection method is not higher than the security level of the control plane security protection method of the second PC5 link.
  • the communication device 700 is used to implement the relay function in the above method:
  • a transceiver unit 702 configured to send a direct connection communication request from the first terminal device to the second terminal device;
  • the direct connection communication request includes an indication of a security termination policy, and the indication of the security termination policy is used to indicate a secure termination The point is on the relay;
  • a processing unit 701, configured to determine the PC5 user plane security protection method of the first PC5 link according to the PC5 user plane security policy of the relay and the PC user plane security policy of the first terminal device;
  • the transceiver unit 702 is further configured to send the PC5 user plane security protection method of the first PC5 link to the second terminal device;
  • the transceiver unit 702 is further configured to receive first information from the second terminal device, where the first information is used to indicate the user plane security protection method of the first PC5 link and the user plane security protection of the second PC5 link method;
  • the processing unit 701 is further configured to activate the user plane security protection method of the second PC5 link and activate the user plane security protection method of the first PC5 link according to the first information; the second PC5 link The user plane security protection method of the link is the same as the user plane security protection method of the first PC5 link;
  • the first PC5 link is the PC5 link between the relay and the first terminal device;
  • the second PC5 link is the link between the relay and the second terminal device PC5 link.
  • the first information is used to indicate the user plane security protection method of the first PC5 link and the user plane security protection method of the second PC5 link, including:
  • the first information is used to indicate: the user plane integrity protection of the first PC5 link and the user plane integrity protection of the second PC5 link are both enabled or disabled, and/or, the first The user plane confidentiality protection of one PC5 link and the user plane confidentiality protection of the second PC5 link are both enabled or disabled.
  • the transceiver unit 702 is further configured to receive a second request message from the first terminal device, where the second request message includes the PC5 control plane security policy of the first terminal device. Relay PC5 control plane security policy;
  • the processing unit 701 is further configured to determine, according to the PC5 control plane security policy of the relay and the PC5 control plane security policy of the first terminal device, the PC5 control plane security protection method and the method for the first PC5 link.
  • the transceiver unit 702 is further configured to send the PC5 control plane security protection method of the first PC5 link and the PC5 control plane security protection method of the second PC5 link to the second terminal device;
  • the transceiver unit 702 is further configured to receive a control plane security algorithm of the second PC5 link from the second terminal device, where the control plane security algorithm is used to indicate the control plane of the second PC5 link Security and control plane security of the first PC5 link, the control plane security algorithm is based on the PC5 control plane security protection method of the first PC5 link and the PC5 control plane security protection of the second PC5 link method determined;
  • the processing unit 701 is further configured to activate the control plane security protection method of the second PC5 link and the control plane security protection of the first PC5 link according to the control plane security algorithm of the second PC5 link method.
  • control plane security algorithm is used to indicate the control plane security of the second PC5 link and the control plane security protection method of the first PC5 link, including:
  • the control plane security algorithm is used to indicate: the control plane integrity protection of the first PC5 link and the control plane integrity protection of the second PC5 link are both enabled or not enabled, and/or, the Both the control plane confidentiality protection of the first PC5 link and the control plane confidentiality protection of the second PC5 link are enabled or disabled.
  • the security level of the user plane security protection method of the second PC5 link is not higher than the security level of the control plane security protection method of the second PC5 link, and the security level of the first PC5 link The security level of the user plane security protection method is not higher than the security level of the control plane security protection method of the first PC5 link.
  • each functional module in each embodiment of this application may be integrated into one processing unit. In the device, it can also exist physically alone, or two or more modules can be integrated into one module.
  • the above-mentioned integrated modules can be implemented in the form of hardware, and can also be implemented in the form of software function modules.
  • the communication device 700 includes at least one processor 810 and a memory 820 .
  • the computer program is stored in the memory 820 .
  • Memory 820 is coupled to processor 810 .
  • the coupling in the embodiments of the present application is the spaced coupling or communication connection between devices, units or modules, which may be in electrical, mechanical or other forms, and is used for information interaction between the devices, units or modules.
  • the memory 820 may also be located outside the communication device 700 .
  • the processor 810 may cooperate with the memory 820 .
  • the processor 810 may invoke computer programs stored in the memory 820 . At least one of the at least one memory may be included in the processor.
  • the communication apparatus 700 may further include a communication interface 830 for communicating with other devices through a transmission medium, so that the devices used in the communication apparatus 700 may communicate with other devices.
  • communication interface 830 may be a transceiver, circuit, bus, module, or other type of communication interface, and the other device may be other terminal.
  • the processor 810 uses the communication interface 830 to send and receive information, and is used to implement the methods in the above embodiments.
  • the communication interface 830 is used for receiving resource indication information.
  • the communication interface 830 is used to transmit data.
  • the processor may be a general-purpose processor, a digital signal processor, an application-specific integrated circuit, a field programmable gate array or other programmable logic device, a discrete gate or transistor logic device, or a discrete hardware component, which can implement or
  • a general purpose processor may be a microprocessor or any conventional processor or the like.
  • the steps of the methods disclosed in conjunction with the embodiments of the present application may be directly embodied as executed by a hardware processor, or executed by a combination of hardware and software modules in the processor.
  • the memory may be a non-volatile memory, such as a hard disk drive (HDD) or a solid-state drive (SSD), etc., and may also be a volatile memory (volatile memory), for example Random-access memory (RAM).
  • Memory is, but is not limited to, any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer.
  • the memory in this embodiment of the present application may also be a circuit or any other device capable of implementing a storage function, for storing computer programs and/or data.
  • the methods provided in the embodiments of the present application may be implemented in whole or in part by software, hardware, firmware, or any combination thereof.
  • software When implemented in software, it can be implemented in whole or in part in the form of a computer program product.
  • the computer program product includes one or more computer instructions.
  • the computer When the computer program is loaded and executed on a computer, all or part of the processes or functions described in the embodiments of the present invention are generated.
  • the computer may be a general purpose computer, a special purpose computer, a computer network, network equipment, user equipment, or other programmable apparatus.
  • the computer instructions may be stored in or transmitted from one computer-readable storage medium to another computer-readable storage medium, for example, the computer instructions may be downloaded from a website site, computer, server, or data center Transmission to another website site, computer, server or data center by wire (eg coaxial cable, optical fiber, digital subscriber line, DSL for short) or wireless (eg infrared, wireless, microwave, etc.).
  • the computer-readable storage medium can be any medium that can be accessed by a computer, or a data storage device such as a server, data center, etc. that includes one or more medium integrations.
  • the medium may be a magnetic medium (eg, a floppy disk, a hard disk, a magnetic tape), an optical medium (eg, a digital video disc (DVD)), or a semiconductor medium (eg, an SSD), or the like.

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Abstract

本申请公开了一种安全通信方法、装置及系统，该方法包括：第二终端设备接收来自中继的关于第一终端设备的第一请求消息；第一请求消息包括第一终端设备的PC5用户面安全策略和中继的PC5用户面安全策略；第二终端设备根据第二终端设备的PC5用户面安全策略、第一终端设备的PC5用户面安全策略、中继的PC5用户面安全策略，确定第一信息；第二终端设备向中继发送第一信息，第一信息用于指示第一PC5链路的用户面安全保护方法和第二PC5链路的用户面安全保护方法；其中，第一PC5链路的用户面安全保护方法和第二PC5链路的用户面安全保护方法相同。

Description

一种安全通信方法、装置及系统 技术领域
本申请涉及通信技术领域，尤其涉及一种安全通信方法、装置及系统。
背景技术
目前，设备到设备(device to device，D2D)通信允许用户设备(user equipment，UE)之间直接进行通信。
当某一终端设备(如远端(remote)UE)处于通信网络的覆盖范围之外，或者在与通信网络中的接入网设备之间的通信质量较差的情况下，可以基于D2D通信，通过中继(如中继(relay)UE)与通信网络建立非直接通信，中继可以建立用于传输远端设备的协议数据单元(protocol data unit，PDU)会话，将从远端UE接收的数据通过该PDU会话传输至数据网络，或将通过PDU会话从数据网络获取的数据发送至远端UE。
在这种终端设备通过中继通信的场景下，究竟如何实现中继两端的链路对于用户面数据的安全保护的协同处理，是需要解决的问题。
发明内容
本申请提供一种安全通信方法、装置及系统，用以实现中继两端的链路对于用户面数据的安全保护的协同处理。
第一方面，提供第一种安全通信方法，该方法可由通信装置执行，通信装置可以是第二终端设备或能够支持第二终端设备实现该方法所需的功能的通信装置，当然还可以是其他通信装置，例如芯片系统。第一方面中以该通信装置为第二终端设备为例。该方法包括：
第二终端设备接收来自中继的关于第一终端设备的第一请求消息；所述第一请求消息包括所述第一终端设备的PC5用户面安全策略和所述中继的PC5用户面安全策略；根据第二终端设备的PC5用户面安全策略、所述第一终端设备的PC5用户面安全策略、所述中继的PC5用户面安全策略，确定第一信息；向所述中继发送所述第一信息，所述第一信息用于指示第一PC5链路的用户面安全保护方法和第二PC5链路的用户面安全保护方法；其中，所述第一PC5链路的用户面安全保护方法和第二PC5链路的用户面安全保护方法相同；
其中，所述第一PC5链路为所述中继与所述第一终端设备之间的PC5链路；所述第二PC5链路为所述中继与所述第二终端设备之间的PC5链路。
通过执行本申请实施例所提供的方法，能够在各设备间实现对于用户面安全保护的协同处理，例如，可以使得各个设备要么均激活用户面数据的完整性保护方法，要么均不激活用户面数据的完整性保护方法，从而使各个设备在处理方式上保持一致。
在一种可能的实现中，第一信息用于指示第二PC5链路的用户面安全保护方法。因为本申请实施例是避免在安全激活发生在分段的情况下，两段链路的用户面安全保护方法不一致，因此第一信息用于指示第二PC5链路的用户面安全保护方法还可以理解为第一信息用于指示第一PC5链路的用户面安全保护方法和第二PC5链路的用户面安全保护方法，包括：
所述第一信息用于指示：所述第一PC5链路的用户面完整性保护和/或所述第二PC5 链路的用户面完整性保护均开启或均不开启，和/或，所述第一PC5链路的用户面机密性保护和/或所述第二PC5链路的用户面机密性保护均开启或均不开启。
本申请实施例中，可以保证第一PC5链路的用户面安全保护方法和第二PC5链路的用户面安全保护方法相同。
在一种可能的实现中，该方法还包括:
接收来自中继的关于所述第一终端设备的第二请求消息，所述第二请求消息包括所述第一终端设备的PC5控制面安全策略所述中继的PC5控制面安全策略；
根据所述第二终端设备的PC5控制面安全策略、所述第一终端设备的PC5控制面安全策略和所述中继的PC5控制面安全策略，确定第二PC5链路的控制面安全算法；
所述第二终端设备向所述中继发送所述第二PC5链路的控制面安全算法，所述控制面安全算法用于指示所述第二PC5链路的控制面安全保护方法和所述第一PC5链路的控制面安全保护方法，其中，所述第一PC5链路的控制面安全保护方法和第二PC5链路上激活的控制面安全保护方法相同。
本申请实施例中，因第一PC5链路的控制面安全保护方法和第二PC5链路的控制面安全保护方法相同，所以可以避免在安全激活发生在分段的情况下(如UE-1的安全终结点策略采用跳到跳(hop-to-hop)安全)，两段链路的控制面安全的不一致。
需要说明的是，在安全激活不发生在分段的情况下，两段链路的控制面安全保护方法可以不一致。
在一种可能的实现中，所述第二请求消息中还包括安全终结点策略的指示，所述安全终结点策略的指示用于指示安全终结点位于所述中继上。
本申请实施例中，可以保证在安全激活发生在分段的情况下，第一PC5链路的用户面安全和第二PC5链路的用户面安全保护方法相同。
在一种可能的实现中，所述控制面安全算法用于指示所述第二PC5链路的控制面安全保护方法和所述第一PC5链路的控制面安全保护方法，包括
所述控制面安全算法用于指示：所述第一PC5链路的控制面完整性保护和所述第二PC5链路的控制面完整性保护均开启或均不开启，和/或，所述第一PC5链路的控制面机密性保护和所述第二PC5链路的控制面机密性保护均开启或均不开启。
本申请实施例中，可以保证第一PC5链路的控制面安全保护方法和第二PC5链路上激活的控制面安全保护方法相同，提高链路的安全性。
在一种可能的实现中，根据所述第二终端设备的PC5用户面安全策略、所述第一终端设备的PC5用户面安全策略和所述中继的PC5用户面安全策略，确定第一信息，包括：
根据所述第二终端设备的PC5用户面安全策略、所述第一终端设备的PC5用户面安全策略和所述中继的PC5用户面安全策略，以及所述第二PC5链路的控制面安全算法，确定所述第一信息；
其中，所述第二PC5链路的用户面安全的安全等级不高于所述第二PC5链路的控制面安全的安全等级，所述第一PC5链路的用户面安全的安全等级不高于所述第一PC5链路的控制面安全的安全等级。
本申请实施例中，可以满足目前用户面安全的安全等级不高于控制面安全的安全等级的要求。
在一种可能的实现中，所述第二PC5链路的用户面安全不高于所述第二PC5链路的控 制面安全，所述第一PC5链路的用户面安全的安全等级不高于所述第一PC5链路的控制面安全，包括：
当第三PC5链路的控制面机密性保护开启，则所述第三PC5链路的用户面机密性保护开启或不开启；
当所述第三PC5链路的控制面机密性保护不开启，则所述第三PC5链路的用户面机密性保护不开启；
当所述第三PC5链路的控制面完整性保护开启，则所述第三PC5链路的用户面完整性保护开启或不开启；
当所述第三PC5链路的控制面完整性保护不开启，则所述第三PC5链路的用户面完整性保护不开启；
其中，所述第三PC5链路为所述第二PC5链路或者所述第一PC5链路。
本申请实施例中，可以满足目前用户面安全的安全等级不高于控制面安全的安全等级的要求。
第二方面，提供第一种安全通信方法，该方法可由通信装置执行，通信装置可以是第二终端设备或能够支持第二终端设备实现该方法所需的功能的通信装置，当然还可以是其他通信装置，例如芯片系统。第一方面中以该通信装置为第二终端设备为例，该方法包括：
第二终端设备通过至少一个中继接收来自第一终端设备的直连通信请求；所述直连通信请求包括安全终结点策略的指示，所述安全终结点策略的指示用于指示安全终结点位于中继上；
第二终端设备接收来自所述至少一个中继所确定的第一PC5链路的PC5控制面安全保护方法和第二PC5链路的PC5控制面安全保护方法；
第二终端设备根据所述第二终端设备的PC5控制面安全策略，以及所述至少一个中继所确定的第一PC5链路的PC5控制面安全保护方法，确定目标中继；
第二终端设备接收来自所述目标中继所确定的第一PC5链路的PC5用户面安全保护方法；
第二终端设备根据来自所述目标中继的第一PC5链路的PC5用户面安全保护方法，和所述第二终端设备的PC用户面安全策略，确定第一信息；
第二终端设备向所述中继发送所述第一信息，所述第一信息用于指示第一PC5链路的用户面安全和第二PC5链路的用户面安全保护方法；其中，所述第一PC5链路的用户面安全和第二PC5链路的用户面安全保护方法相同；
其中，所述第一PC5链路为所述中继与所述第一终端设备之间的PC5链路；所述第二PC5链路为所述中继与所述第二终端设备之间的PC5链路。
本申请实施例中，中继可以确定是否激活第二PC5链路和第二PC5链路的用户面安全保护方法，从而通过执行本申请实施例所提供的方法，能够在各设备间实现对于用户面数据的完整性保护的协同处理，例如，可以使得各个设备要么均激活用户面安全性保护方法，要么均不激活用户面数据的完整性保护方法，从而使各个设备在处理方式上保持一致，减小出错的概率。
在一种可能的实现中，所述第一信息用于指示第一PC5链路的用户面安全保护方法和第二PC5链路的用户面安全保护方法，包括：
所述第一信息用于指示：所述第一PC5链路的用户面完整性保护和所述第二PC5链路的用户面完整性保护均开启或均不开启，和/或，所述第一PC5链路的用户面机密性保护和所述第二PC5链路的用户面机密性保护均开启或均不开启。
在一种可能的实现中，第二终端设备根据来自所述目标中继所确定的第一PC5链路的PC5用户面安全保护方法，确定所述第二PC5链路的控制面安全算法；
第二终端设备向所述中继发送第二PC5链路的控制面安全算法，所述第二PC5链路的控制面安全算法用于指示所述第二PC5链路的控制面安全保护方法和所述第一PC5链路的控制面安全保护方法。
本申请实施例中，中继可以确定是否激活第二PC5链路和第二PC5链路的控制面安全保护方法，从而通过执行本申请实施例所提供的方法，能够在各设备间实现对于控制面数据安全保护的协同处理，例如，可以使得各个设备要么均激活用户面数据的完整性保护方法，要么均不激活用户面数据的完整性保护方法，从而使各个设备在处理方式上保持一致，减小出错的概率。
在一种可能的实现中，所述第二PC5链路的控制面安全算法用于指示所述第二PC5链路的控制面安全保护方法和所述第一PC5链路的控制面安全保护方法，包括：
所述第二PC5链路的控制面安全算法用于指示：所述第一PC5链路的控制面完整性保护和所述第二PC5链路的控制面完整性保护均开启或均不开启，和/或，所述第一PC5链路的控制面机密性保护和所述第二PC5链路的控制面机密性保护均开启或均不开启。
在一种可能的实现中，所述第二终端设备根据来自所述目标中继的第一PC5链路的PC5用户面安全保护方法，和所述第二终端设备的PC用户面安全策略，确定第一信息，包括：
所述第二终端设备根据来自所述目标中继的第一PC5链路的PC5用户面安全策略，和所述第二终端设备的PC用户面安全策略，以及所述第二PC5链路的控制面安全算法，确定所述第一信息；
其中，所述第二PC5链路的用户面安全保护方法的安全等级不高于所述第二PC5链路的控制面安全保护方法的安全等级，所述第一PC5链路的用户面安全保护方法的安全等级不高于所述第一PC5链路的控制面安全保护方法的安全等级。
在一种可能的实现中，所述第二PC5链路的用户面安全保护方法不高于所述第二PC5链路的控制面安全保护方法，所述第一PC5链路的用户面安全保护方法的安全等级不高于所述第一PC5链路的控制面安全保护方法，包括：
当第三PC5链路的控制面机密性保护开启，则所述第三PC5链路的用户面机密性保护开启或不开启；
当所述第三PC5链路的控制面机密性保护不开启，则所述第三PC5链路的用户面机密性保护不开启；
当所述第三PC5链路的控制面完整性保护开启，则所述第三PC5链路的用户面完整性保护开启或不开启；
当所述第三PC5链路的控制面完整性保护不开启，则所述第三PC5链路的用户面完整性保护不开启；
其中，所述第三PC5链路为所述第二PC5链路或者所述第一PC5链路。
该方面中的部分实现的有益效果可以参见第一方面，在此不再重复赘述。
第三方面，提供第一种安全通信方法，该方法可由通信装置执行，通信装置可以是第二终端设备或能够支持第二终端设备实现该方法所需的功能的通信装置，当然还可以是其他通信装置，例如芯片系统。第一方面中以该通信装置为第二终端设备为例。该方法包括：
第二终端设备通过至少一个中继接收来自第一终端设备的直连通信请求；
第二终端设备根据安全策略辅助信息，从所述至少一个中继中确定目标中继；
第二终端设备通过所述目标中继与所述第一终端设备通信；
本申请实施例中，按照该方法可以实现从多个中继中选择可以保证建立PC5链路的中继，以便于成功建立PC5连接。
在一种可能的实现中，第二终端设备根据安全策略辅助信息，从所述至少一个中继中确定目标中继，包括：
第二终端设备从所述至少一个中继中选择一个包括可选的PC5控制面安全策略的目标中继。
本申请实施例中，因目标中继的控制面安全策略包括可选的PC5控制面安全策略，所以能够支持建立PC5连接。
在一种可能的实现中，所述安全策略辅助信息包括所述至少一个中继的PC控制面安全策略，以及所述第二终端设备的PC5控制面安全策略；
所述第二终端设备根据安全策略辅助信息，从所述至少一个中继中确定目标中继，包括：
从所述至少一个中继中，选择一个中继的PC控制面安全策略与所述第二终端设备的PC5控制面安全策略不冲突的目标中继。
本申请实施例中，因目标中继的控制面安全策略与所述第二终端设备的PC5控制面安全策略不冲突，所以能够支持建立PC5连接。
在一种可能的实现中，所述安全策略辅助信息包括所述至少一个中继的PC控制面安全策略，以及所述第二终端设备的PC5控制面安全策略；
第二终端设备根据安全策略辅助信息，从所述至少一个中继中确定目标中继，包括：
第二终端设备根据安全策略辅助信息，从所述至少一个中继中，选择一个中继的PC用户面安全保护方法的安全等级不高于所述第二终端设备的PC控制面安全保护方法的安全等级的目标中继。
本申请实施例中，因目标中继PC控制面安全保护方法的安全等级低于中继的PC用户面安全保护方法的安全等级。
在一种可能实现中，所述安全策略辅助信息是策略控制功能网元预先配置的。策略控制功能网元可以优先为目标中继配置可选状态的安全策略。
第四方面，提供第一种安全通信方法，该方法可由通信装置执行，通信装置可以是第中继或能够支持中继实现该方法所需的功能的通信装置，当然还可以是其他通信装置，例如芯片系统。第一方面中以该通信装置为中继为例。该方法包括：
中继向第二终端设备发送关于第一终端设备的第一请求消息；所述第一请求消息包括所述第一终端设备的PC5用户面安全策略和所述中继的PC5用户面安全策略；
中继接收来自第二终端设备的第一信息，所述第一信息用于指示第一PC5链路的用户 面安全保护方法和第二PC5链路的用户面安全保护方法；其中，所述第一PC5链路的用户面安全保护方法和第二PC5链路的用户面安全保护方法相同；
中继根据所述第一信息，激活所述第二PC5链路的用户面安全保护方法，以及激活第一PC5链路的用户面安全保护方法；
其中，所述第一PC5链路为所述中继与第一终端设备之间的PC5链路，所述第二PC5链路为所述中继与所述第二终端设备之间的PC5链路。
本申请实施例中，因第一PC5链路的用户面安全保护方法和第二PC5链路的用户面安全保护方法相同，所以可以避免在安全激活发生在分段的情况下(如UE-1的安全终结点策略采用跳到跳(hop-to-hop)安全)，两段链路的用户面安全的不一致。通过执行本申请实施例所提供的方法，能够在各设备间实现对于用户面安全保护的协同处理，例如，可以使得各个设备要么均激活用户面数据的完整性保护方法，要么均不激活用户面数据的完整性保护方法，从而使各个设备在处理方式上保持一致，减小出错的概率。
在一种可能的设计，该方法还包括：
中继向所述第二终端设备发送所述第一终端设备的控制面安全策略和所述中继的控制面安全策略，第一终端设备的控制面安全策略和所述中继的控制面安全策略用于确定所述第二PC5链路的控制面安全算法；
中继接收来自第二终端设备的所述第二PC5链路的控制面安全算法，所述控制面安全算法用于指示所述第二PC5链路的控制面安全和所述第一PC5链路的控制面安全；
中继根据所述第二PC5链路的控制面安全算法，激活所述第二PC5链路的控制面安全，以及所述第一PC5链路的控制面安全，其中，所述第一PC5链路的控制面安全和第二PC5链路上激活的控制面安全相同。
本申请实施例中，通过执行本申请实施例所提供的方法，能够在各设备间实现对于控制面安全保护的协同处理，例如，可以使得各个设备要么均激活控制面数据的完整性保护方法，要么均不激活控制面数据的完整性保护方法，从而使各个设备在处理方式上保持一致，减小出错的概率。
在一种可能的实现中，中继的PC5控制面安全保护方法的安全等级不高于所述第二链路的PC5用户面安全保护方法的安全等级。
在一种可能的实施例中，所述第一PC5链路的用户面安全保护方法的安全等级不高于所述第一PC5链路的控制面安全保护方法的安全等级；第二PC5链路的用户面安全保护方法的安全等级不高于所述第二PC5链路的控制面安全保护方法的安全等级。
该第四方面中的部分实现的有益效果可以参见第一方面，在此不再重复赘述。
第五方面，提供第一种安全通信方法，该方法可由通信装置执行，通信装置可以是第中继或能够支持中继实现该方法所需的功能的通信装置，当然还可以是其他通信装置，例如芯片系统。第一方面中以该通信装置为中继为例。该方法包括：
中继向第二终端设备发送自第一终端设备的直连通信请求；所述直连通信请求包括安全终结点策略的指示，所述安全终结点策略的指示用于指示安全终结点位于中继上；
中继根据所述中继的PC5用户面安全策略和所述第一终端设备的PC用户面安全策略，确定第一PC5链路的PC5用户面安全保护方法；
中继向所述第二终端设备发送所述第一PC5链路的PC5用户面安全保护方法；
中继接收来自所述第二终端设备的第一信息，所述第一信息用于指示第一PC5链路的用户面安全保护方法和第二PC5链路的用户面安全保护方法；
中继根据所述第一信息，激活所述第二PC5链路的用户面安全保护方法，以及激活第一PC5链路的用户面安全保护方法；所述第二PC5链路的用户面安全保护方法和所述第一PC5链路的用户面安全保护方法相同；
其中，所述第一PC5链路为所述中继与所述第一终端设备之间的PC5链路；所述第二PC5链路为所述中继与所述第二终端设备之间的PC5链路。
本申请实施例中，中继可以确定是否激活第二PC5链路和第二PC5链路的用户面安全保护方法，从而通过执行本申请实施例所提供的方法，能够在各设备间实现对于用户面数据的完整性保护的协同处理，例如，可以使得各个设备要么均激活用户面安全性保护方法，要么均不激活用户面数据的完整性保护方法，从而使各个设备在处理方式上保持一致，减小出错的概率。
在一种可能的实现中，所述第一信息用于指示第一PC5链路的用户面安全保护方法和第二PC5链路的用户面安全保护方法，包括：
所述第一信息用于指示：所述第一PC5链路的用户面完整性保护和所述第二PC5链路的用户面完整性保护均开启或均不开启，和/或，所述第一PC5链路的用户面机密性保护和所述第二PC5链路的用户面机密性保护均开启或均不开启。
在一种可能的实现中，所述中继接收来自所述第一终端设备的第二请求消息，所述第二请求消息包括所述第一终端设备的PC5控制面安全策略所述中继的PC5控制面安全策略。
在一种可能的实现中，所述中继根据所述中继的PC5控制面安全策略和所述第一终端设备的PC5控制面安全策略，确定所述第一PC5链路的PC5控制面安全保护方法和所述第二PC5链路的PC5控制面安全保护方法；
所述中继向所述第二终端设备发送所述第一PC5链路的PC5控制面安全保护方法和所述第二PC5链路的PC5控制面安全保护方法；
所述中继接收来自所述第二终端设备的所述第二PC5链路的控制面安全算法，所述控制面安全算法用于指示所述第二PC5链路的控制面安全和所述第一PC5链路的控制面安全，所述控制面安全算法是根据所述第一PC5链路的PC5控制面安全保护方法和所述第二PC5链路的PC5控制面安全保护方法确定的；
所述中继根据所述第二PC5链路的控制面安全算法，激活所述第二PC5链路的控制面安全和所述第一PC5链路的控制面安全。
在一种可能的实现中，所述控制面安全算法用于指示所述第二PC5链路的控制面安全保护方法和所述第一PC5链路的控制面安全保护方法，包括：
所述控制面安全算法用于指示：所述第一PC5链路的控制面完整性保护和所述第二PC5链路的控制面完整性保护均开启或均不开启，和/或，所述第一PC5链路的控制面机密性保护和所述第二PC5链路的控制面机密性保护均开启或均不开启。
在一种可能的实现中，所述第二PC5链路的用户面安全保护方法的安全等级不高于所述第二PC5链路的控制面安全保护方法的安全等级，所述第一PC5链路的用户面安全保护方法的安全等级不高于所述第一PC5链路的控制面安全保护方法的安全等级。
该方面中的部分实现的有益效果可以参见第一方面，在此不再重复赘述。
第六方面，本申请提供一种通信装置。该装置具有实现上述第一方面至第三方面的各实施例的功能。该功能可以通过硬件实现，也可以通过硬件执行相应的软件实现。该硬件或软件包括一个或多个与上述功能相对应的模块。
在一种可能的设计中，该装置包括：收发单元，可选地，还包括处理单元。所述处理单元例如可以是处理器，所述接收单元例如可以是接收器，所述发送单元，例如可以是发送器，所述接收器和发送器包括射频电路。可选地，所述装置还包括存储单元，该存储单元例如可以是存储器。当该装置包括存储单元时，该存储单元存储有计算机执行指令，该处理单元与该存储单元连接，该处理单元执行该存储单元存储的计算机执行指令，以使该装置执行上述第一方面至第三方面任意一项的方法。
在另一种可能的设计中，该装置为芯片。该芯片包括：接收单元和发送单元，可选地，还包括处理单元。所述处理单元例如可以是处理电路，所述接收单元例如可以是输入接口、管脚或电路等，所述发送单元例如可以是输出接口、管脚或电路等。该处理单元可执行存储单元存储的计算机执行指令，以使上述第一方面至第三方面任意一项的发送方法被执行。可选地，所述存储单元为所述芯片内的存储单元，如寄存器、缓存等，所述存储单元还可以是所述终端内的位于所述芯片外部的存储单元，如只读存储器(read-only memory，ROM)、可存储静态信息和指令的其他类型的静态存储设备、随机存取存储器(random access memory，RAM)等。
其中，上述任一处提到的处理器，可以是一个通用的中央处理器(Central Processing Unit，CPU)，微处理器，特定应用集成电路(application-specific integrated circuit，ASIC)，或一个或多个用于控制上述第一方面至第三方面的方法的程序执行的集成电路。
第七方面，本申请提供一种通信装置。该装置具有实现上述第四方面或第五方面的各实施例的功能。该功能可以通过硬件实现，也可以通过硬件执行相应的软件实现。该硬件或软件包括一个或多个与上述功能相对应的模块。
在一种可能的设计中，该装置包括：收发单元，可选地，还包括处理单元。所述处理单元例如可以是处理器，所述接收单元例如可以是接收器，所述发送单元，例如可以是发送器，所述接收器和发送器包括射频电路。可选地，该装置还包括存储单元，该存储单元例如可以是存储器。当该装置包括存储单元时，该存储单元存储有计算机执行指令，该处理单元与该存储单元连接，该处理单元执行该存储单元存储的计算机执行指令，以使该接入与移动性管理功能网元执行上述第四方面或第五方面任意一项的方法。
在另一种可能的设计中，该装置为芯片。该芯片包括：接收单元和发送单元，可选地，还包括处理单元。所述处理单元例如可以是处理电路，所述接收单元例如可以是输入接口、管脚或电路等，所述发送单元例如可以是输出接口、管脚或电路等。该处理单元可执行存储单元存储的计算机执行指令，以使上述第四方面或第五方面任意一项的发送方法被执行。可选地，所述存储单元为所述芯片内的存储单元，如寄存器、缓存等，所述存储单元还可以是所述终端内的位于所述芯片外部的存储单元，如只读存储器(read-only memory，ROM)、可存储静态信息和指令的其他类型的静态存储设备、随机存取存储器(random access memory，RAM)等。
其中，上述任一处提到的处理器，可以是一个通用的中央处理器(Central Processing Unit，CPU)，微处理器，特定应用集成电路(application-specific integrated circuit，ASIC)， 或一个或多个用于控制上述第四方面或第五方面的方法的程序执行的集成电路。
第八方面，本申请实施例提供一种芯片系统，该芯片系统包括处理器，还可以包括存储器，用于实现上述第一方面、第二方面或第三方面任一种设计示例中第一通信装置执行的方法。该芯片系统可以由芯片构成，也可以包含芯片和其他分立器件。
第九方面，本申请实施例提供一种芯片系统，该芯片系统包括处理器，还可以包括存储器，用于实现上述第四方面或第五方面任一种设计示例中第二通信装置执行的方法。该芯片系统可以由芯片构成，也可以包含芯片和其他分立器件。
第十方面，本申请提供一种通信系统，包括上述第六方面任一种设计示例中的通信装置和上述第七方面任一种设计示例中的通信装置。可选地，所述该通信系统中还包括网络数据分析功能(network data analytics function，NWDAF)网元。
第十方面，本申请实施例中还提供一种计算机可读存储介质，存储介质中存储有计算机程序或指令，当计算机程序或指令被执行时，可实现上述第一方面、第二方面或第三方面任一种设计示例中的方法。
第十一方面，本申请实施例中还提供一种计算机可读存储介质，存储介质中存储有计算机程序或指令，当计算机程序或指令被执行时，可实现上述第四方面或第五方面任一种设计示例中的方法。
第十二方面，本申请实施例中还提供一种计算机程序产品，包括指令，当其在计算机上运行时，使得计算机执行上述第一方面、第二方面或第三方面中任一种设计示例中第一通信装置执行的方法。
第十三方面，本申请实施例中还提供一种计算机程序产品，包括指令，当其在计算机上运行时，使得计算机执行上述第四方面或第五方面中任一种设计示例中第二通信装置执行的方法。
另外，第六方面至第十三方面中任一种设计方式所带来的技术效果可参见第一方面至第五方面中不同设计方式所带来的技术效果，此处不再赘述。
附图说明
图1A和图1B为本申请实施例提供的一种系统的架构图；
图2A和图2B为本申请实施例提供的通信场景示意图；
图3为本申请实施例提供的一种安全策略获取方法示意图；
图4为本申请实施例提供的安全通信方法示意图；
图5为本申请实施例提供的另一种安全通信方法示意图；
图6为本申请实施例提供的另一种安全通信方法示意图；
图7～图8为本申请实施例提供的一种通信装置的结构示意图。
具体实施方式
为了使本申请实施例的目的、技术方案和优点更加清楚，下面将结合附图对本申请实施例作进一步地详细描述。
下面先介绍本申请涉及到的术语的定义。
1、PC5连接与PC5连接建立流程：
本申请实施例中的PC5连接是指基于PC5接口的终端设备之间的通信连接。
本申请实施例中的PC5连接建立流程用于在支持PC5接口的至少2个终端设备之间建立通信连接。其中，PC5连接建立完成后，至少2个终端设备可以利用PC5连接进行控制面信令协商和/或用户面数据传递。本申请实施例中的PC5连接建立流程可以包括PC5单播连接建立(one-to-one communication)流程和PC5多播连接建立(one-to-many communication)流程。PC5单播连接建立流程用于在支持PC5接口的2个终端设备之间建立通信连接，PC5多播连接建立流程用于在支持PC5接口的2个以上终端设备之间建立通信连接。本申请下述实施例均是示例性的以2个终端设备之间建立通信连接为例进行说明，即本申请下述实施例均是示例性的以PC5单播连接建立流程为例进行说明。PC5多播连接建立流程中任意2个终端设备之间建立通信连接的方式可参考PC5单播连接建立流程中2个终端设备之间建立通信连接的流程，在此统一说明，以下不再赘述。
2、安全策略：
安全策略是用于描述是否开启安全保护的策略，可用于确定安全保护方法。本申请实施例中用于不同场景的安全策略包括PC5用户面安全策略和PC5控制面安全策略中的至少一种，其中，PC5用户面安全策略包括PC5连接中的用户面机密性保护策略和PC5连接中的用户面完整性保护策略中的至少一种；PC5控制面安全策略包括PC5连接中的控制面机密性保护策略和PC5连接中的控制面完整性保护策略中的至少一种；也就是说，安全策略至少包括以下至少一种：
PC5连接中的控制面机密性保护策略；
PC5连接中的控制面完整性保护策略；
PC5连接中的用户面机密性保护策略；
或者，PC5连接中的用户面完整性保护策略。
其中，控制面机密性保护即保护信令在传输过程中的机密性；控制面完整性保护即保护信令在传输过程中的完整性；用户面机密性保护即保护用户面数据在传输过程中的机密性；用户面完整性保护即保护用户面数据在传输过程中的完整。本申请实施例中，完整性是指获取到的信令或数据与原始的信令或数据一致，没有被修改，因此，完整性保护是为了使得攻击者“攻击不成”。机密性是指无法被直接看出真实内容，因此机密性保护是为了使得攻击者“读不懂”。此外，本申请实施例中的机密性保护也可以称为加密保护，在此统一说明，以下不再赘述。
本申请实施例中，PC5连接中的控制面机密性保护策略与PC5连接中的控制面完整性保护策略属于PC5连接中的PC5控制面安全策略；PC5连接中的用户面机密性保护策略与PC5连接中的用户面完整性保护策略属于PC5连接中的PC5用户面安全策略，在此统一说明，以下不再赘述。
本申请实施例中，安全策略共分有开启(REQUIRED)，不开启(NOT NEEDED)和可选(PREFERRED)三种。或者，REQUIRED翻译为需要开启安全，NOT NEEDED翻译为不需要开启安全，PREFERRED翻译为偏好开启或者称为可选开启，即可以开启安全但也可以不开启安全，在此统一说明，以下不再赘述。
示例性的，以PC5连接中的控制面机密性保护策略为例，则PC5连接中的控制面机密性保护策略包括：PC5连接中的控制面机密性保护开启(REQUIRED)、PC5连接中的控 制面机密性保护不开启(NOT NEEDED)、或者PC5连接中的控制面机密性保护可选(PREFERRED)。PC5连接中的控制面机密性保护策略、PC5连接中的用户面机密性保护策略、或者PC5连接中的用户面完整性保护策略的示例可参考PC5连接中的控制面机密性保护策略的示例，在此不再赘述。
需要说明的是，本申请实施例中，安全策略在被发送时，一般情况下只会选择三种策略(REQUIRED、NOT NEEDED和PREFERRED)中的一种策略发送，在某些特殊的场景下可能会选择至少2种发送，并且其中一个是PREFERRED。比如，在发送NOT NEEDED和PREFERRED时，代表倾向不开启安全保护；在发送REQUIRED和PREFERRED时，则代表倾向开启安全保护。
需要说明的是，本申请实施例中，PC5连接中的控制面机密性保护策略、PC5连接中的控制面完整性保护策略、PC5连接中的用户面机密性保护策略；或者，PC5连接中的用户面完整性保护策略中的多种保护策略可以相同，本申请实施例对此不做具体限定。
3、安全能力：
本申请实施例中的安全能力包括以下至少一种：
PC5连接中支持的一个或者多个控制面机密性保护算法；
PC5连接中支持的一个或者多个控制面完整性保护算法；
PC5连接中支持的一个或者多个用户面机密性保护算法；
或者，PC5连接中支持的一个或者多个用户面完整性保护算法。
其中，控制面机密性保护算法是指一种用于保护控制面的机密性保护算法。控制面完整性保护算法是指一种用于保护控制面的完整性保护算法。用户面机密性保护算法是指一种用于保护用户面的机密性保护算法。用户面完整性保护算法是指一种用于保护控制面的用户面保护算法。其中，PC5连接中支持的一个或者多个控制面机密性保护算法与PC5连接中支持的一个或者多个控制面完整性保护算法属于PC5连接中的控制面安全能力；PC5连接中支持的一个或者多个用户面机密性保护算法与PC5连接中支持的一个或者多个用户面完整性保护算法属于PC5连接中的用户面安全能力，在此统一说明，以下不再赘述。
需要说明的是，本申请实施例中，PC5连接中支持的一个或者多个控制面机密性保护算法、PC5连接中支持的一个或者多个控制面完整性保护算法、PC5连接中支持的一个或者多个用户面机密性保护算法、或者PC5连接中支持的一个或者多个用户面完整性保护算法中的多种保护算法可以相同或者存在共同项，本申请实施例对此不做具体限定。
4、安全算法，可以包括用户面安全算法(即用户面使用的安全算法)和信令面安全算法(即信令面使用的安全算法)。用户面使用的安全算法用于保护用户面数据，可以包括用户面加密算法和用户面完整性算法。信令面使用的安全算法用于保护信令，可以包括信令面加密算法和信令面完整性算法。
5、安全密钥，可以包括用户面安全密钥和信令面安全密钥。其中，用户面安全密钥用于保护用户面数据，可以包括用户面加密密钥和用户面完整性保护密钥。信令面安全密钥用于保护信令，例如可以是保护无线资源控制(radio resource control，RRC)信令的密钥，即RRC密钥，RRC密钥可以包括RRC加密密钥和RRC完整性保护密钥。
6、激活用户面/信令面安全，指的是在确定出用户面/信令面安全保护方法的情况下，可以开始使用用户面/信令面安全算法和用户面/信令面安全密钥来激活该用户面/信令面安全，即可以开始使用用户面/信令面安全保护方法、用户面/信令面安全算法和用户面/信令 面安全密钥来对将要传输的用户面数据/信令进行安全保护。例如，确定的用户面安全保护方法为开启用户面机密性保护+不开启用户面完整性保护，用户面加密算法为加密算法A，用户面加密密钥为密钥K，则对于将要传输的用户面数据，采用加密算法A和密钥K对该用户面数据进行用户面机密性保护。激活用户面安全保护方法可以达到的效果是执行激活用户面安全的节点可以开始对用户面数据进行安全保护和开始对用户面数据进行解安全保护。需要理解的是，安全保护和解安全保护这两个动作可能是进一步分开激活的。比如基站在发送安全激活消息后，则基站激活解安全保护；基站再收到安全激活确认消息后，基站激活安全保护。
7、安全保护与解安全保护：
本申请实施例中的安全保护是指使用安全保护方法对用户面数据/控制面信令进行保护；本申请实施例中的解安全保护是指根据安全保护方法还原用户面数据/控制面信令。其中，这里的安全保护方法包括机密性保护和/或完整性保护是否开启，在此统一说明，以下不再赘述。
具体的，当机密性保护开启时，可以使用加密密钥和加密算法对用户面数据/控制面信令进行加密保护；当完整性保护开启时，可以使用完整性保护密钥和完整性保护算法对用户面数据/控制面信令进行完整性保护。当然，本申请实施例中，当完整性保护不开启时，也可以使用消息完整性检验码(message Integrity check，MIC)对用户面数据/控制面信令进行完整性保护，本申请实施例对此不作具体限定。其中，MIC的相关说明参考后续实施例，在此不再赘述。此外，需要说明的是，当需要对用户面数据/控制面信令进行加密保护和完整性保护时，可以对用户面数据/控制面信令先进行加密保护，再进行完整性保护；也可以对用户面数据/控制面信令先进行完整性保护，再进行加密保护，本申请实施例不限定加密保护和完整性保护的执行顺序，在此统一说明，以下不再赘述。
具体的，当机密性保护开启时，可以使用加密密钥和加密算法对用户面数据/控制面信令进行解密；当完整性保护开启时，可以使用完整性保护密钥和完整性保护算法对用户面数据/控制面信令进行完整性保护验证。当然，本申请实施例中，当完整性保护不开启时，若使用MIC对用户面数据/控制面信令进行完整性保护，则相应的，可以使用期望MIC对用户面数据/控制面信令进行完整性保护验证，本申请实施例对此不作具体限定。其中，期望MIC的相关说明参考后续实施例，在此不再赘述。此外，可以理解的是，当同时对用户面数据/控制面信令进行机密性保护和完整性保护时，如果用户面数据/控制面信令先被机密性保护，再被完整性保护，则解安全保护的顺序是先进行完整性保护验证、再对加密后的用户面数据/控制面信令进行解密；如果用户面数据/控制面信令先被完整性保护，再被加密，则解安全保护的顺序是先对加密后的用户面数据/控制面信令进行解密，再进行完整性保护验证，在此统一说明，以下不再赘述。
PC5连接的控制面使用的安全保护方法，用于保护PC5连接的控制面信令中传递的全部参数或部分参数。其中，PC5连接的控制面使用的安全保护方法例如可以包括PC5连接的控制面的机密性保护和/或完整性保护是否开启。
PC5连接的用户面使用的安全保护方法，用于保护PC5连接的部分或全部用户面数据。其中，PC5连接的用户面使用的安全保护方法例如可以包括PC5连接的用户面的机密性保护和/或完整性保护是否开启。
需要说明的是，本申请实施例中，PC5连接的控制面使用的安全保护方法也可以称之 为PC5连接的控制面信令使用的安全保护方法；PC5连接的用户面使用的安全保护方法也可以称之为PC5连接的用户面数据使用的安全保护方法，在此统一说明，以下不再赘述。
参阅图1A所示，一种本申请适用的具体的控制面系统架构示意图。该系统架构中的网元包括终端设备(user equipment，UE)，图1A中示例性的绘制了四个UE，分别为UE A、UE B、UE C、UE D。系统架构还包括无线接入网(radio access network，RAN)、接入和移动性管理功能(access and mobility management function，AMF)网元、会话管理功能(session management function，SMF)网元、用户面功能(user plane function，UPF)网元、统一数据管理(unified data management，UDM)网元、统一数据仓储(unified data repository，UDR)网元、应用功能(application function，AF)网元、数据网络(data network，DN)、能力开放网元(network exposure function，NEF)网元、5G直连通信发现名称管理功能(5G direct discovery name management function，5GDDNMF)网元、策略控制功能(policy control function，PCF)网元、邻近业务应用服务器(ProSe application server)等。其中，AMF网元、SMF网元、UDM网元、NEF网元、PCF网元等网元属于第五代移动通信技术(5th generation mobile networks，5G)网络架构中的核心网网元，这里仅示例性的展示了部分核心网网元，该系统架构中还可以包括其他核心网网元。
终端设备是一种具有无线收发功能的设备，可以部署在陆地上，包括室内或室外、手持或车载；也可以部署在水面上(如轮船等)；还可以部署在空中(例如飞机、气球和卫星上等)。所述终端设备可以是手机(mobile phone)、平板电脑(pad)、带无线收发功能的电脑、虚拟现实(virtual reality，VR)终端、增强现实(augmented reality，AR)终端、工业控制(industrial control)中的无线终端、无人驾驶(self driving)中的无线终端、远程医疗(remote medical)中的无线终端、智能电网(smart grid)中的无线终端、运输安全(transportation safety)中的无线终端、智慧城市(smart city)中的无线终端、智慧家庭(smart home)中的无线终端等。在本申请实施例中的终端设备可以为能够在邻近业务(proximity service，ProSe)场景下进行通信的终端设备，该终端设备具备邻近业务应用(ProSe application)功能，具备ProSe application功能的终端设备间可以通过PC5口通信。
本申请实施例中涉及三种终端设备，分别为第一终端设备、中继设备和第二终端设备，第一终端设备可以请求其他终端设备(包括第二终端设备)为第一终端设备提供邻近业务，第二终端设备在能够为第一终端设备提供邻近业务时，为第一终端设备提供邻近业务，第二终端设备和第一终端设备可以进行直接通信，也可以通过中继设备进行通信。
在不同发现场景中，提供邻近业务的第二终端设备和需要邻近业务的第一终端设备的名称不同，这里介绍两种发现场景，分别为开放邻近业务发现(open ProSe discovery)场景和受限邻近业务发现(restricted ProSe discovery)场景。开放邻近业务发现场景和受限邻近业务发现场景的相关描述可参考现有技术，在此不再赘述。
举个例子，比如一个用户A使用终端设备A打游戏，用户A没有明确的游戏伙伴，只要“随机”找到一个游戏伙伴就行，该场景为开放邻近业务场景。若用户A使用终端设备A打游戏有明确的伙伴，则用户A可以通过终端设备A“指定”一个伙伴，只有他指定的伙伴才能接入游戏，其他的则不行，该场景为受限邻近业务发现场景。
可选的，本申请实施例中，发现场景中的发现模式包括模式A(model A)或模式B(model B)。model A和model B的区别在于发现场景中终端设备发起发现(discovery) 方式不同。
model A的含义是“我在这”，model A中涉及的终端设备分为播报方UE(announcing UE)和监听方UE(monitoring UE)，announcing UE广播“我在这”，monitoring UE接收到announcing UE广播的消息后根据是否符合自己业务需求确定是否与announcing UE建立连接。
model B的含义是“谁在那？/你在哪？”，model B中涉及的终端设备分为被发现者UE(discoveree UE)和发现者UE(discoverer UE)，discoverer UE发起请求，该请求中包括特定的信息，如谁在那？/你在哪？”，discoveree UE接收到discoverer UE发起的请求之后根据自己是否可以提供业务服务来确定是否回复该请求，若回复响应，说明“我在这”。本申请实施例中，开放邻近业务发现场景只适用于model A发现模式，而受限邻近业务发现场景适用于model A和model B两种发现模式。
本申请实施例中，网络侧(如核心网网元或5G DDNMF网元)可以根据第一终端设备或第二终端设备上报给网络侧的邻近业务信息确定第一终端设备或第二终端设备类型，例如，第一终端设备或第二终端设备上报给网络侧的邻近业务信息包括的发现命令能够指示第一终端设备或第二终端设备是一个announcing UE还是一个monitoring UE；是一个响应终端设备(response UE)还是一个请求终端设备(queryUE)。其中，announcing UE与monitoring UE为上述model A中的两端终端设备，Response UE与QueryUE分别对应上述model B中的discoveree UE和discoverer UE。
在申请实施例中，第二终端设备在向第一终端设备提供邻近业务之前，需要先验证下第一终端设备的身份，确定第二终端设备是否为一个真正需要邻近业务的终端设备。具体的，第二终端设备可以将从第一终端设备获取的消息完整码发上报给核心网网元或5G DDNMF网元，其中，该消息完整码是基于第一终端设备的发现密钥生成的，第一终端设备的发现密钥是利用从核心网网元或5G DDNMF网元获取的密钥生成参数生成的。由核心网网元或5G DDNMF网元基于第二终端设备上报的消息完整码和5G DDNMF网元根据第一终端设备的发现密钥计算的期望消息完整码进行验证。第二终端设备也可以从核心网网元或5G DDNMF网元获得与第一终端设备的发现密钥，由第二终端设备计算期望消息完整码进行验证。
类似的，第一终端设备在接受第二终端设备提供的邻近业务之前，也可以先验证下第二终端设备的身份，确定第二终端设备是否为一个真正能提供邻近业务的终端设备。具体方式与第二终端设备验证第一终端设备的身份的方式类似。
RAN的主要功能是控制用户通过无线接入到移动通信网络。RAN是移动通信系统的一部分。它实现了一种无线接入技术。从概念上讲，它驻留某个设备之间(如移动电话、一台计算机，或任何远程控制机)，并提供与其核心网的连接。
AMF网元负责终端的接入管理和移动性管理，在实际应用中，其包括了LTE中网络框架中MME里的移动性管理功能，并加入了接入管理功能。
可选的，AMF网元还能够利用Kamf生成终端设备的发现密钥，将终端设备的发现密钥发送给5GDDNMF网元或其他网元(如ProSe application server)。
其中，Kamf为终端设备的一种根密钥，是终端设备在注册到网络时，网络侧(如AMF网元)为终端设备分配的，分别保存在终端设备和AMF侧的密钥。
SMF网元负责会话管理，如用户的会话建立等。
PCF网元是由运营商提供的控制面功能，用于向SMF网元提供会话的策略。策略可以包括计费相关策略、QoS相关策略和授权相关策略等。
UPF网元是用户面的功能网元，主要负责连接外部网络，其包括了LTE的服务网关(serving gateway，SGW)和公用数据网网关(public data network gateway，PDN-GW)的相关功能。
DN负责为终端提供服务的网络，如一些DN为终端提供上网功能，另一些DN为终端提供短信功能等等。
UDM网元可存储用户的签约信息，实现类似于4G中的HSS，在本申请实施例中，UDM能够根据UE的匿名化标识或临时标识确定UE的用户永久性标识(subscription permanent identifier，SUPI)。
UDR网元主要用来存储用户的签约信息、策略数据、用于开放的结构化数据、应用数据。
AF网元可以是第三方的应用控制平台，也可以是运营商自己的设备，AF网元可以为多个应用服务器提供服务。
NEF网元将其他网元的能力和事件开放给第三方合作伙伴或AF网元。它为AF网元提供了一种安全地向第三代合作伙伴计划(3rd generation partnership project,3GPP)网络提供信息的方法，NEF网元可以验证和授权并协助限制AF网元。此外，NEF网元还可以将AF网元交换的信息和核心网功能网元交换的信息进行转换。
邻近业务应用服务器(ProSe application server)，存储邻近业务的用户标识，还可以对发现场景中的终端设备进行验证。还可以存储为终端设备预配置的密钥，该密钥是与邻近业务相关的密钥。
在实际应用中，邻近业务应用服务器(ProSe application server)可以为AF网元，也即具备Prose Application server的功能的AF网元。这样，Prose application server与UE可以通过UE-RAN-UPF-AF的路径，进行用户面通信。Prose application server还可以通过NEF网元与其他核心网网元进行通信。比如通过NEF网元与PCF网元通信。
5GDDNMF网元在开放邻近业务发现场景中，可以分配邻近业务应用标识(ProSe application ID)和邻近业务应用代码(ProSe application code)，以及处理邻近业务应用标识(ProSe application ID)和邻近业务应用代码(ProSe application code)之间的映射。5GDDNMF网元在受限邻近业务发现场景中，可以跟ProSe application server通过PC2口通信，用于处理发现请求(discovery request)的授权，分配受限邻近业务应用标识(ProSe discovery UE ID)和受限的邻近业务代码(ProSe restricted code)，以及处理邻近业务应用标识(ProSe discovery UE ID)和受限的邻近业务代码(ProSe restricted code)之间的映射。其中，邻近业务应用代码(ProSe application code)和受限的邻近业务代码(ProSe restricted code)均可以作为本申请实施例中提及的邻近业务临时标识。
在本申请实施例中，5GDDNMF网元增加了安全功能，能够验证终端设备(如第一终端设备和第二终端设备)的身份。例如，5GDDNMF网元在接收到第二终端设备上报的来自第一终端设备的消息完整码后，可以利用第一终端设备的发现密钥生成期望消息完整码，在确定消息完整码和期望消息完整码一致后，通知第二终端设备对第一终端设备验证成功。
需要说明的是，这里仅是以5GDDNMF网元增加了安全功能为例进行说明，该安全功能也可以增加在其他网元中，如核心网网元或ProSe application Server，由其他网元与终端 设备交互，验证其他终端设备的身份。
尽管未示出，核心网网元还包括认证服务功能(authentication server function，AUSF)网元、应用程序的身份验证和密钥管理锚点功能(authentication and key management for applications(AKMA)anchor function，AAnF)网元、引导服务功能(bootstrapping server function，BSF)等，AUSF网元具有鉴权服务功能，在本申请实施例中AUSF网元能够利用终端设备的Kausf生成终端设备的发现密钥，将终端设备的发现密钥发送给5GDDNMF网元。类似的，AAnF网元能够利用Kakma生成终端设备的发现密钥，将终端设备的发现密钥发送给5GDDNMF网元。引导服务功能(bootstrapping server function，BSF)网元能够利用Ks生成终端设备的发现密钥，将终端设备的发现密钥发送给5GDDNMF网元。
其中，Kausf、Kakma、或Ks也作为生成终端设备的发现密钥所使用根密钥，这些密钥是终端设备在注册到网络时，网络侧为终端设备分配的，保存在网络侧的密钥，且该密钥与终端设备自己生成的、保存在终端设备侧的密钥相同。
图1B为本申请适用的具体的用户面系统架构示意图。其中的网元的功能的介绍可以参考图1A中对应的网元的功能的介绍，不再赘述。用户面架构主要是指UEA通过用户面与5G DDNMF交互，即UE先接入5GC完成用户面建立，然后UEA与5G DDNMF通过用户面交互。
图1B与图1A的主要区别在于：UE A连接5G DDNMF的方式不同，控制面架构主要是指UE通过控制面与5G DDNMF交互，即，UE通过NAS消息先查找到AMF，然后AMF转发NAS消息给5G DDNMF。
图2A为UE到网络中继(UE-to-Network Relay)系统架构，该系统架构中显示一个UE可以有2种方式、3条路径接入网络。2种方式分别是UE和网络直连方式(即图中所示的路径#1)和UE通过中继(Relay)接入网络方式(即图中所示的路径#2和路径#3)。
另外，图2B示出UE-1和UE-2通过中继进行通信的架构。此时中继(Relay)作为UE-1和UE-2之间通信的媒介，通过中继，UE-1和UE-2就可以进行通信了。
目前，针对图2B所示的UE-1和UE-2通过中继进行通信的场景，由于当前并没有定义中继两端的链路(如图2B所示的第一PC5链路和第二PC5链路，或第一PC5链路和Uu链路)之间的安全保护方法的激活结果的关系，当安全激活发生在分段的情况下(如UE-1的安全终结点策略采用跳到跳(hop-to-hop)安全)，可能会发生两段链路的安全保护不一致。示例性地，假设中继两端的链路的安全保护分别为：UE-1到中继之间的第一PC5链路为有用户面机密性保护开启，用户面完整性保护开启；但是中继到UE-2之间的第二PC5链路为用户面机密性保护不开启，用户面完整性保护开启。这样就造成了用户面数据只有在第一PC5链路才会进行机密性保护，也就是说，攻击者可以从中继到UE-2之间的链路中非法获得用户面数据，因此，UE-1到中继之间的第一PC5链路的机密性保护就失去了意义，而且还浪费了UE1和中继的处理性能。可见，目前UE到网络中继(UE-to-Network Relay)这一系统的通信方式尚存在安全性不足的问题。
为此，本申请实施例提供一种安全通信方法，该方法包括：中继设备根据中继设备与第二终端设备之间的第二PC5链路的用户面保护方法，确定中继设备与第一终端设备之间的第一PC5链路的用户面保护方法，从而保证两段链路的用户面安全保护结果的一致性。 以避免因两段PC5链路所使用的用户面安全保护方法不一致，导致用户面安全保护失败的问题。
接下来结合附图介绍本申请实施例提供的技术方案。
在本申请的各个实施例中，可能涉及到的标识包括但不限于以下的至少一种：
1、终端标识。
终端标识可以包括国际移动用户识别码(international mobile subscriber identification number，IMSI)、永久设备标识(permanet equipment identifier，PEI)、用户永久性标识(subscriber permanent identifier，SUPI)、用户隐藏标识(subscriber concealed identifier，SUCI)、临时移动用户标识(temporary mobile subscriber identity，TMSI)、IP多媒体公共标识(IP multimedia public identity，IMPU)、媒体接入控制(media access control，MAC)地址、IP地址、手机号码或全球唯一临时UE标识(globally unique temporary UE identity，GUTI)中的至少一项。例如终端标识只包括IMSI，或者只包括PEI和SUPI，或者只包括PEI、TMSI和IMPU，或者包括IMSI、PEI、SUPI、SUCI、TMSI、IMPU、MAC地址、IP地址、手机号码和GUTI，等等，在此不作限制。在后续的实施例中，统一用UEID来表示终端标识。
其中，PEI为终端设备的固定标识；IMSI为在LTE系统中用户的唯一永久标识；SUPI为5G系统中用户的永久标识；SUCI为对SUPI进行加密后得到的用户标识。
下面结合附图，对本申请实施例提供的一种安全通信方法进行说明，本申请实施例提供的安全通信方法包括两部分，第一部分：安全策略配置方法；第二部分：中继设备或第二终端设备决定PC5链路的用户面安全保护方法和控制面安全保护方法。下面对两部分分别进行说明：
第一部分：
参见图3，对本申请实施例提供的一种安全策略配置方法进行说明，该方法包括：
步骤301，终端设备向AMF发送NAS消息，该消息用于触发AMF向终端设备提供预置数据，该预置数据用于后续近距离通信(prose)场景下的PC5链路建立。
具体地，终端设备可以通过RAN将该NAS消息发送给AMF。
示例性地，该NAS消息可以是终端设备的安全策略预置数据请求(UE policy provisioning request)消息。该消息中可以包括终端设备的终端标识(如5G-GUTI))、终端设备的近距离通信角色指示信息(如remote indication和/或relay indication)。
其中，终端标识用于网络侧设备确定是哪个终端设备发起的请求。比如，网络设备可以通过5G-GUTI确定出UE的SUPI，并且根据UE的SUPI获得UE的网络侧数据，比如近距离(Prose)通信场景下的签约数据。
近距离通信角色指示信息用于网络侧设备确定该UE在Prose场景下可以作为哪种类型的UE接入网络。比如说，UE是作为一个普通UE接入网络；还是可以作为服务于其它UE的中继接入网络，以便于为其它UE转发与接入网之间的数据(或者为其它UE转发和另一个UE之间的数据)；还是可以作为一个远端(remote)UE接入网络，远端UE是指一个UE需要通过中继才能与另一个UE(或者网络)实现连接并且交互数据。换句话说，远端UE在没有中继UE的辅助下，是无法连接到网络(或者连接到另一个UE)的。
示例性地，近距离通信角色指示信息的指示方式可能存在如下几种可能的实现方式。
第一种可能的实现方式：将近距离通信角色指示信息设置为“0”表示不需要作为中 继，此时“0”在网络侧的理解可以有2种：(1)、该UE可以作为远端UE，但不作为中继UE，此时可以理解为所有UE都可以作为远端UE；(2)、该UE既不可以作为远端UE，又不可以作为中继。本实施例不限制具体理解方式。设置为“1”表示可以作为中继。此时“1”在网络侧的理解可以有2种：(1)、该UE只能作为中继；(2)、该UE既可以作为远端UE，又可以作为中继。本实施例不限制具体理解方式。
第二种可能的实现方式：将近距离通信角色指示信息设置为“00”表示不需要作为远端UE，也不需要作为中继；设置为“01”代表不可以作为远端UE，但是可以作为中继；设置为“10”代表可以作为远端UE，但是不可以作为中继；设置为“11”代表既可以作为远端UE，又可以作为中继。
第三种可能的实现方式：近距离通信角色指示信息还可以是字符串，比如“远端(remote)”、“中继(relay)”、“远端和中继(remote&Relay)”。本实施例不限制可以同时出现的字符串的个数。也就是说，在只有可以使用“远端(remote)”、“中继(relay)”者2个字符串的情况下，这2个字符串可以同时传递，表示UE可以同时作为2个角色。如果只出现一种，则表示只能作为一种角色。在3种字符串都支持的情况下，则“远端(remote)”代表该UE只能作为远端UE，“中继(relay)”表示该UE只能作为中继UE，“远端和中继(remote&Relay)”该UE既可以作为远端UE，又可以作为中继UE。
步骤302，AMF检查该终端设备的授权信息。
具体地，AMF需要检查该终端设备传递的身份指示信息是否合法，即是否可以做一个远端UE(Remote UE)，或者是，AMF需要检查该终端设备是否可以作为中继，再或者，当近距离通信角色指示信息指示该终端设备既可以作为远端UE，也可以作为中继时，AMF需要同时做上述两种身份的检查。
具体的，一种检查授权的实现方式可以是：AMF与UDM进行交互，从UDM获得该终端设备的Prose通信场景下的签约数据。AMF根据签约数据确定该终端设备是否可以作为中继和/或远端UE。当然，AMF也可以从PCF获取终端设备的签约数据，或者通过能力开放网元从Prose应用服务器获取终端设备的签约数据，本实施例对此并不作限制。
另一种检查授权的实现方式可以是：AMF可以从PCF获取终端设备的授权信息的检查结果。即PCF与UDM进行交互，从UDM获得该终端设备的Prose场景下的签约数据。PCF根据签约数据确定该终端设备是否可以作为中继和/或远端UE，然后PCF将检查结果发送至AMF。当然，PCF也可以者通过能力开放网元从Prose应用服务器或者其它设备上获取终端设备的签约数据，本实施例对此并不作限制。
步骤303，当AMF对终端设备的授权检查成功后，AMF向PCF发送请求消息，该消息用于请求终端设备的安全策略预置数据。
示例性地，AMF向PCF发送(pcf_UEPolicyControl_Update)消息，该消息中包括终端设备的近距离通信角色指示信息(如remote UE indication/relay UE indication)。可选地，该消息中还携带终端设备的近距离(Prose)通信相关信息(如UE的Prose身份信息：Prose User ID，Prose应用信息，Prose APP ID等)。
步骤304，PCF确定终端设备的安全策略。
具体地，PCF根据终端设备的近距离通信角色指示信息，当确定该终端设备可以作为中继时，PCF确定该终端设备作为中继(中继身份)所使用的安全策略；当确定该终端设备可以作为远端UE时，PCF确定该终端设备作为远端UE(远端身份)所使用的安全策略。 当确定该终端设备为普通UE时，PCF确定该终端设备作为普通UE所使用的安全策略。其中，安全策略可以包括PC5控制面安全策略和/或PC5用户面安全策略。当确定该终端设备既可以作为中继，又可以作为远端UE时，PCF可以分别确定该终端设备作为中继所使用的安全策略，以及作为远端UE所使用的安全策略。
在一种可能的实施例中，PCF可以进一步与其他网元(比如5G DDNMF)交互，以获取更多该终端设备的Prose相关信息。比如Prose APP Code，Prose APP Code用于UE之间发现的。
步骤305，PCF向AMF发送响应消息，该响应消息包括终端设备的安全策略。
具体地，PCF向AMF回复Nafm_Communication_N1N2MessageTransfer消息，该消息中包括普通身份的安全策略和非普通身份的安全策略中的至少一种类型。其中，非普通身份就包括中继身份或者远端身份。
一种可能的情况下，若该消息只携带一种安全策略，则表示该安全策略不仅可以被用于普通接入，还可以被用于远端(remote)身份和/或中继身份接入(如果UE支持这些身份的话)。
另一种可能的情况下，如果该消息携带两种安全策略，则一种代表普通身份使用的安全策略，另一种代表非普通身份使用的安全策略。
再一种可能的情况下，如果该消息携带三种安全策略，则分别代表普通身份使用的安全策略、远端身份使用的安全策略和中继身份使用的安全策略。
在本申请实施例中，在所有UE都可以作为远端身份的情况下，那么远端身份也可以属于普通身份的一种，此时非普通身份就只包含中继身份。如果不是所有的UE都可以使用远端身份，那么非普通身份就包括中继身份和远端身份。
步骤306，AMF向UE转发该终端设备的安全策略。
步骤307，终端设备接收该安全策略，并保存至本地设备中。
需要说明的是，上述PCF也可以是其它能够提供安全的网元，所谓提供安全策略的网元是网络侧分配策略的网元或功能实体，比如5G中的PCF，4G中的(policy and charging rules function)策略与计费规则功能单元，PCRF)，和未来网络中继承相关功能的网元。
在一种可能的实施例中，在上述步骤304中，PCF所确定的终端设备的安全策略可以有多种粒度。比如，可以是PCF粒度，即向该PCF请求的所有终端设备均对应相同的安全策略；再比如，可以是UE粒度，即不同的终端设备可能对应不同的安全策略；再比如，可以是APP粒度，即不同的APP ID对应的终端设备可能对应不同的安全策略；再比如，可以是UE+APP粒度，即不同的UE+APP绑定关系，终端设备可能对应不同的安全策略。
需要说明的是，虽然安全策略可以分为普通身份的安全策略和非普通身份的安全策略，但是不同身份的终端设备的安全策略可以相同，也可以不同。例如远端UE和中继UE这两种身份的终端设备对应的安全策略可以相同，也可以不同。
另外，安全策略也可以分别与远端或中继的身份绑定后进行存储，即存储两种身份的安全策略。比如，UE1的安全策略包括远端身份的安全策略和中继身份的安全策略。比如，普通身份的安全策略包括控制面机密性保护为PREFERRED，控制面完整性保护为REQUIRED，用户面机密性保护为NOT NEEDED，用户面完整性保护为REQUIRED；非普通身份的安全策略包括控制面机密性保护为PREFERRED，控制面完整性保护为PREFERRED，用户面机密性保护为PREFERRED，用户面完整性保护为PREFERRED。 当然，如果UE1的不同身份的安全策略一样，也可以只存储一种身份的安全策略。比如，控制面机密性保护为PREFERRED，控制面完整性保护为PREFERRED，用户面机密性保护为PREFERRED，用户面完整性保护为PREFERRED。本实施例不限制存储方式，即在具体的实施过程中，可以只使用其中一种实现方式，也可以多种实现方式并存。
在一种可能的实施例中，一种保证链路建立的方法是：在安全策略的配置方式中，普通身份使用的安全策略(类似于V2X中端对端通信(one-to-one communication)流程中使用的安全策略)可以包括开启和不开启两种状态。比如，控制面机密性保护为开启，控制面完整性保护为可选，用户面完整性保护为不开启，用户面机密性保护为可选。非普通身份使用的安全策略为只包含可选的安全策略，即只包含“PREFERRED”状态，不包含“REQUIRED”状态和“NOT NEEDED”状态。
这样做的好处是，保证有中继的通信场景下的消息链路是可以建立的。因为在现有技术中，如果图2B所示的UE-1、UE-2和中继之间任意二者的安全策略如果是截然相反的状态(如UE-1的控制面机密性安全策略是REQUIRED状态，UE-2的控制面机密性安全策略是NOT NEEDED状态)，那么UE-2或者中继会释放掉连接，因此链路无法建立。因此，如果中继的安全策略中包括不开启和可选两种状态，则可能因为中继有很明确的安全策略，而导致中继场景下的消息链路无法建立。
另一种保证链路建立的方法是：具有共同属性的UE分配相同的但不含有“PREFERRED”状态的安全策略。具有共同属性是指业务粒度相同，或者其它属性信息相同，其它属性信息可以是某种可以把一部分UE归类到一起的属性信息。这样的话，只会在这些UE范围内使用中继建立业务，那么进而可以保证不会因为中继而无法建立链路。
此外，在一种可能的实施例中，PCF还存储有安全终结点策略、安全算法策略中的至少一种，PCF所确定终端设备的安全策略还可以包括终端设备的安全终结点策略、终端设备安全算法策略中的至少一种。
1)安全终结点策略是安全终结点是应该或者倾向放在中继上，还是不应该或者不倾向放在中继上。其中，“应该”是一种强制性动作，必须要满足的意思。“倾向”的含义是优选，可以不满足。
比如，当比特位信息只有1位时，并且值为0时，表示安全终结点应该或倾向放在中继上，当值为1时，表示安全终结点不应该或者不倾向放在中继上。再比如，当比特位信息为至少2位时，00表示安全终结点必须放在中继上，01表示安全终结点倾向放在中继上，10表示安全终结点倾向不放在中继上，11表示安全终结点必须不放在中继上。再比如，还可以用字符串“end”、“hop”、“prefer”分别表示必须不放在中继上，必须放在中继上和倾向放在中继上。
2)安全算法策略是指应该或者倾向使用128bit的算法还是使用256bit的算法。可以使用比特位指示信息表示，也可以使用字符串表示。
比如，当比特位信息只有1位时，0代表应该或者倾向使用128bit算法，1代表应该或者倾向使用256bit算法。再比如，当比特位信息为至少2位时，00表示必须用128bit算法，01表示倾向用128bit算法，10表示倾向用256bit算法，11表示必须用256bit算法。再比如，还可以用字符串128、256、prefer分别表示必须用128bit算法，必须用256bit算法或者都可以。
上述安全终结点策略和安全算法策略可以使用与安全策略相同的粒度信息，也就是说 这些策略与安全策略的粒度相同；也可以使用与安全策略不同的粒度信息，也就是说这些策略与安全策略的粒度不同。本实施例不做规定。
其中，安全策略的粒度信息是指安全策略可以作用的范围。比如当安全策略是APP ID粒度的时候，那就意味着某一个APP ID对应的安全策略不可以被用在其他APP ID上。再比如，当安全策略是UE粒度的，那就意味着这个UE的所有业务都使用相同的安全策略。本发明不限制PCF为UE存储单一的安全策略，即PCF可以为某些UE只存储UE粒度的安全策略。也可以为UE只存储APP ID粒度的安全策略。也可以为UE存储不同粒度的安全策略。比如为一个UE存储某一个APP ID对应的安全策略和除了这个APP ID外的对应的安全策略，此时可以将除了这个APP ID外的对应的安全策略理解为UE粒度的。
可选地，在上述步骤305中，响应消息中还可以携带安全策略的粒度信息。比如每个Prose APP ID有对应的安全策略，当安全策略与粒度信息结合在一起时，那么就出现了以下几种可能的表示方法，下列表示方法可以用于UE和PCF的存储，用于步骤305消息中的传递的信远的表示方法，本申请实施例不限制其使用场景。
1)、{普通身份的安全策略，非普通身份的安全策略＝(Prose APP ID-1的安全策略，Prose APP ID-2的安全策略，默认安全策略)}；该方法的意思是有一个普通身份的安全策略。该安全策略在UE不作为远端UE和中继UE下使用。在所有UE都可以作为远端UE的情况下，那么该安全策略就是只在UE不作为中继UE的情况下使用的安全策略。还包括有一个Prose APP ID为1的非普通身份的安全策略和Prose APP ID为2的非普通身份的安全策略和默认的非普通身份的安全策略。当非普通身份包括远端身份和中继身份2种时，此时Prose APP ID-1的安全策略可以包括至少1种非普通身份的安全策略，比如针对Prose APP ID-1，那么可以只包括的Prose APP ID-1对应的中继身份的安全策略，还可以既包括Prose APP ID-1对应的中继身份的安全策略又包括Prose APP ID-1的远端身份的安全策略。需要说明的是，该方法Prose APP ID代表的是安全策略对应的粒度信息。因此可以理解为若PC5安全粒度不是Prose APP ID的粒度，则可以将Prose APP ID替换为安全策略对应的粒度。比如，若是UE粒度，则可以将Prose APP ID改成SUPI。
如果Prose APP ID-1的安全策略只包含一种安全策略，则可以理解为该安全策略在可以用被2种身份使用。
若进一步地表示为：{普通身份的安全策略，非普通身份的安全策略＝(Prose APP ID-1的中继身份的安全策略，Prose APP ID-2的远端身份的安全策略，默认安全策略)}，则可以理解为包括了Prose APP ID-1的中继身份的安全策略，Prose APP ID-2的远端身份的安全策略和默认的除了Prose APP ID-1和Prose APP ID-2之外的非普通身份的安全策略。此时，如果该UE在Prose APP ID-1下可以使用远端身份，则该远端身份的安全策略就是默认的非普通身份的安全策略。同理，如果Prose APP ID-2可以使用中继身份，则其中继身份的安全策略就是默认的非普通身份的安全策略。
2)、或者{Prose APP ID-1＝(普通身份的安全策略，非普通身份的安全策略)，{Prose APP ID-2＝(普通身份的安全策略，非普通身份的安全策略)，默认安全策略}；该表示方法中，Prose APP ID-1和Prose APP ID-2代表粒度信息。该方法表示在Prose APP ID-1可以使用的普通身份的安全策略和非普通身份的安全策略，和Prose APP ID-2可以使用的普通身份的安全策略和非普通身份的安全策略是什么。以及其他APP的任何身份都可以使用的默认的安全策略。详细描述可以参考方法1)中的描述。
3)、或者{Prose APP ID-2＝(普通身份的安全策略，非普通身份的安全策略)，非普通身份的默认安全策略，普通身份的默认安全策略}。该方法表示Prose APP ID-2可以使用的普通身份的安全策略和非普通身份的安全策略和在其他Prose APP下普通身份可以使用的默认的安全策略和非普通身份可以使用的默认的安全策略。详细描述可以参考方法1)中的描述。
4){普通身份的安全策略，非普通身份的安全策略}，该方法表示UE粒度的情况下，该UE的普通身份使用的安全策略和非普通身份使用的安全策略。其中，非普通身份的安全策略可以包括远端身份的安全策略和中继身份的安全策略中的至少一种。究竟携带哪种要根据UE请求时携带的身份指示信息确定。如果2种身份都携带，则2种非普通身份的安全策略都需要携带。
5){普通身份的安全策略，中继身份的安全策略}，该表示方法表示UE粒度的情况下，该UE的普通身份的安全策略和中继身份的安全策略。该表示方法适用于所有UE都有远端身份，则远端身份就是普通身份中的一种，即，可以复用普通身份的安全策略。
6){安全策略}，该表示方法表示UE粒度的情况下，该UE的普通身份的安全策略、远端身份和中继身份使用相同的的安全策略。
其中，非普通身份的安全策略包括中继身份的安全策略、远端身份的安全策略中的至少一种。
本申请实施例中，实现了在终端设备通过中继通信的场景下，PCF为终端设备配置安全策略，例如优先将中继的安全策略配置为PREFERRED的安全策略，这样可以保证中继PC5链路的建立，另外还包括安全策略可以有粒度信息，用于保证安全策略的作用范围。需要说明的是，安全策略和粒度的绑定关系多种多样，本申请实施例仅是给出一些参考实例，本申请实施例不限制安全策略和粒度的使用方式。
第二部分：
结合第一部分，本申请实施例提供一种安全通信方法，请参见图4，为该方法的流程图。在下文的介绍过程中，以该方法应用于图2A或图2B所示的网络架构为例。另外，该方法可由第一通信装置执行，该第一通信装置可以是终端设备，或为能够支持终端设备实现该方法所需的功能的通信装置，例如终端设备包括的部件，或者终端设备中的芯片系统等。
为了便于介绍，在下文中，以该方法由终端设备执行为例，对本申请实施例提供的小区选择方法进行详细介绍。
图4为本申请实施例提供的一种安全通信方法流程示意图，该方法可以包括如下步骤。
步骤401、第一终端设备广播第一直连通信请求(direct communication request，DCR)消息。
其中，该第一DCR消息中携带第一终端设备的PC5控制面安全策略。
在一种可能的实施例中，该第一DCR消息中还可以携带第一终端设备的安全终结点策略，该安全终结点策略用于确定安全终结点是否在中继上。例如，当该第一DCR消息中携带“hop-by-hop”安全终结点策略，则安全终结点在中继上；当该第一DCR消息中携带“end-to-end”安全终结点策略，则安全终结点不在中继上。可选地，在一种可能的实施例中，该第一DCR消息中还可以安全算法策略。
所述第一DCR消息中携带的第一终端设备的PC5控制面安全策略为远端身份的PC5控制面安全策略。当第一终端只从网络侧获得一个PC5控制面安全策略的情况下，所述第一DCR消息中携带的第一终端设备的PC5控制面安全策略根据图3所述实施例从网络侧获取到PC5控制面安全策略。
在一种可能的实施例中，该第一DCR消息中还可以携带第一终端设备的PC5控制面安全策略的粒度信息(如APP ID)，该粒度信息，用于第一终端设备的PC5控制面安全策略的作用范围。
其中，该第一DCR消息是广播消息，会被不同的中继接收到。该PC5控制面安全策略可以包括普通身份的PC5控制面安全策略和非普通身份的PC5控制面安全策略中的至少一种。
在一种可能的实施例中，该消息中还可以携带第一终端设备支持的PC5控制面安全算法，以便于第二终端设备确定第二PC5链路的PC5控制面安全算法。
步骤402，至少一个中继接收到第一DCR消息后，向第二终端设备发送第二DCR消息。第二DCR消息由至少一个中继生成并发送。
在一种实现方式中，第二DCR消息可以直接就是第一DCR消息，即至少一个中继直接向第二终端设备转发第一DCR消息。
在另一种实现方式中，第二DCR消息也可以包含中继的相关信息和第一终端设备的相关信息。第一终端设备的相关信息来自第一DCR消息。第一终端设备的相关信息可以是全部第一DCR消息或第一DCR消息的一部分内容。中继的相关信息可以包括中继的PC5控制面安全策略、中继的PC5控制面安全算法等。
在一种可能的实施例中，中继在向第二终端设备转发该第二DCR消息之前，需要先判断该中继是否能够为第一终端设备服务。需要说明的是，该判断过程可以发生在上述步骤401之前，该判断过程也可以发生在上述步骤401之后。比如，第一终端设备发送第二DCR消息之前，中继能够通过发现(discovery)流程确定是否能够为第一终端设备服务，如果可以服务，则中继会接收该第一DCR消息并生成第二DCR消息，如果不可以，中继直接拒收该第一DCR消息。再比如，在没有discovery(发现)流程的情况下，该中继在收到该第一DCR消息后先根据消息中的信息判断是否可以为第一终端服务，如果可以，则中继接收该第一DCR消息并生成第二DCR消息，如果不可以，中继直接拒收该第一DCR消息。比如通过消息中携带的应用层ID信息判断。本实施例不限制，至少一个中继的个数，可以是一个，或者是两个以上。
在一种可能的实施例中，至少一个中继判断是否可以支持第一终端设备的控制面安全策略，如果可以支持则生成第二DCR消息并发送第二DCR消息给第二终端设备。如果不支持，则不需要为第一终端设备生成第二DCR消息。具体地，至少一个中继判断中继的PC5控制面机密性保护策略和PC5控制面完整性保护策略是否与第一终端设备的PC5控制面机密性安全策略相冲突。比如，假设第一终端设备的PC5控制面安全策略为PC5控制面机密性保护为NOT NEEDED和第一终端设备的PC5控制面完整性保护是REQUIRED，那么第一终端设备不可以选择PC5控制面机密性保护为REQUIRED，或者PC5控制面完整性保护为NOT NEEDED的中继。这里，NOT NEEDED和REQUIRED是冲突的。
在一种可能的实施例中，中继还可以向第二终端设备发送中继的PC5控制面安全策略、安全终结点策略和安全算法策略中的至少一个。需要说明的是，上述与中继相关的安全策 略等承载方式因第二DCR消息的格式不同而不同。比如，当中继发送的第二DCR消息就是直接转发第一终端设备的DCR消息是，那么上述与中继相关的安全策略可以承载在中继向第二终端设备转发的DCR消息中，或者，当第一DCR消息或者第一DCR消息的一部分作为第二DCR消息的一个container(内容)、一个IE或一些IE时，上述与中继相关的安全策略可以承载在其与第一DCR消息不相关的IE中，本实施例不做限制。需要说明的是：第二DCR消息还可以携带第一终端设备支持的控制面安全算法和/或中继支持的控制面安全算法。具体携带方法可以参考上述关于安全策略携带方法的相关描述。
步骤403，第二终端设备从至少一个中继中确定用于为第一终端服务的中继。
需要说明的是，本实施例中，该步骤403是可选的步骤。一种可能的情况下，在只有一个中继向第二终端设备转发DCR消息时，上述步骤403可以不用执行。这时，第二终端设备只需要在判断该中继是否支持该业务，若是，则确定该中继为可以为第一终端服务的中继。比如，第二终端设备根据是否对消息中携带的应用信息感兴趣进行判断。
另一种可能的情况下，在有两个以上的中继向第二终端设备转发DCR消息时，第二终端设备根据收到的第一终端设备的PC5控制面安全策略、至少两个中继的PC5控制面安全策略、第二终端设备的PC5控制面安全策略、第一终端设备的安全终结点策略、至少两个中继的安全终结点策略、第二终端设备的安全终结点策略、第一终端设备的安全算法策略、至少两个中继的安全算法策略、第二终端设备的安全算法策略中的至少一种，从至少两个中继中确定为第一终端服务的中继。
需要说明的是，在一种可能的实现方式中，因不同中继向第二终端设备转发DCR消息的顺序有先有后，所以，第二终端设备可以根据接收到来自不同中继的转发消息先后顺序，从至少两个中继中确定一个为第一终端服务的中继。例如，假设第二终端设备最先收到来自第一中继发送的第二DCR消息，则第二终端设备可以根据一终端设备的PC5控制面安全策略、第一中继的PC5控制面安全策略、第二终端设备的PC5控制面安全策略、第一终端设备的安全终结点策略、第一中继的安全终结点策略、第二终端设备的安全终结点策略、第一终端设备的安全算法策略、第一中继的安全算法策略、第二终端设备的安全算法策略中的至少一种，确定该第一中继是否可用用于建立PC5链路。若是，则确定第一中继为目标中继，即可用于建立PC5链路；如果不可以，则再根据接收时间先后次序，对其它中继依次执行上述判断。
在另一种可能的实现方式中，第二终端设备可以随机选择一个中继发送的第二DCR消息进行判断。以此类推，直至确定满足条件的目标中继。本申请实施例不限制具体的判断的中继的选择顺序。
具体地，第二终端设备可以采用如下至少一种方式确定目标中继。
方式一，第二终端设备根据第二终端设备的安全终结点确定目标中继。
示例性的，如果第二终端设备的预配置的或者从网络侧得到的安全终结点策略是跳到跳(hop-by-hop)，那么，第二终端设备只能从至少两个中继中选择一个支持“hop-by-hop”或者支持PREFERRED的安全策略的目标中继。再比如，如果第二终端设备的预配置的或者从网络侧得到的安全终结点策略是点到点(End-to-End)，那么，第二终端设备只能从至少两个中继中选择一个支持End-to-End或者支持PREFERRED的安全策略目标中继。
方式二，第二终端设备根据每种组合下的各个终端设备的PC5控制面安全策略确定中继。
其中，假设有两个中继(第一中继和第二中继)向第二终端设备发送第二DCR消息，那么就存在两种组合，第一种组合包括第一终端设备、第一中继和第二终端设备；第二种组合包括第一终端设备、第二中继和第二终端设备。
示例性地，如果第二终端设备预配置的PC5控制面安全策略包括不开启的PC5控制面安全策略(是指控制面机密性保护和控制面完整性保护至少有一个是NOT NEEDED的)，那么第二终端设备不可以选择与第二终端设备预配置的PC5控制面安全策略相冲突(是指对应的控制面机密性保护和控制面完整性保护至少有一个是REQUIRED)的中继。比如，假设第二终端设备的PC5控制面安全策略为PC5控制面机密性保护为NOT NEEDED和PC5控制面完整性保护是REQUIRED，那么第二终端设备不可以选择PC5控制面机密性保护为REQUIRED，或者PC5控制面完整性保护为NOT NEEDED的中继。这里，NOT NEEDED和REQUIRED就是冲突的。进一步地，可选地，如果第二终端设备先判断安全终结点是hop-by-hop，那么再按上述步骤选择中继。反之，如果第二终端设备的预配置安全终结点是End-to-End安全，则选择中继的时候不需要参考中继的PC5控制面安全策略。此时，可以按照3GPP标准TS 33.536中的5.3.3.1.4.3章节确定与第一终端设备的控制面安全保护方法。
方式三，第二终端设备根据每种组合下的各个设备的PC5控制面安全策略、第二终端设备的PC5用户面安全策略和第二终端设备的PC5用户面安全策略一起确定中继。
换句话来说，如果在用户面安全保护不可以高于控制面安全保护的原则下，为了保障PC5连接的建立，第二终端设备在选择中继的时候可以参考使用第二终端设备的PC5用户面安全策略。其中，用户面安全保护不可以高于控制面安全保护的具体含义包括以下几个方面：1)如果控制面机密性保护激活，那么用户面机密性保护可以激活、也可以不激活。2)如果控制面完整性保护激活，那么用户面完整性保护可以激活，也可以不激活。3)如果控制面机密性保护不激活，那么用户面机密性保护不激活。4)如果控制面完整性保护不激活，那么用户面完整性保护不激活。
具体地，原则一：如果第二终端设备的PC5用户面安全策略有“REQUIRED”状态，那么相应第二终端设备选择的中继的PC5控制面安全策略也应该为“REQUIRED”状态。示例性地，如果第二终端设备的PC5的用户面机密性保护和/或用户面完整性保护为“REQUIRED”状态，那么第二终端设备只能选择PC5的控制面机密性保护和/或控制面完整性保护为“REQUIRED”的中继。原则二：如果第二终端设备的PC5用户面安全有“NOT NEEDED”状态，那么相应的第二终端设备选择的中继的PC5控制面安全策略不可以为“REQUIRED”。示例性地。如果PC5的用户面机密性保护和/或用户面完整性保护为“NOT NEEDED”状态，那么第二终端设备只能选择PC5的控制面机密性保护和/或控制面完整性保护不为“REQUIRED”的中继。
方式四，第二终端设备根据中继的安全算法策略和第二终端设备的安全算法策略确定中继。
具体地，原则一，在第二终端设备只支持128-bit算法的情况下，第二终端设备不可以选择一个只支持256-bit算法的中继；原则二，在第二终端设备只支持256-bit算法的情况下，第二终端设备不可以选择一个只支持128-bit算法的中继。
需要说明的是，本申请实施例并不限制PC5用户面安全策略、PC5控制面安全策略和安全终结点策略这3种策略的执行先后顺序，同时因为有些安全策略是可选的，因此可以 不执行，本申请实施例也不限制三种安全策略的结合和使用方法。
需要补充说明的是：如果安全终结点策略是标准规定好的，即标准规定了只能使用hop-by-hop或者End-to-End，那么安全终结点策略就是不需要的，并且在执行其它步骤的时候要默认按照相关的规定执行。
假设第一终端设备发送的第一DCR消息中包括第一终端设备的安全终结点策略为“hop-by-hop”安全策略，目标中继为第一中继，则下文中以安全终结点位于目标中继上进行说明。
步骤404，在第二终端设备确定第一中继后，与该第一中继发起鉴权流程。
需要说明的是，本实施例中，该步骤404是本实施例的可选步骤。
该鉴权流程的作用是完成第二终端设备和第一中继之间的相互信任，并生成保护控制面和用户面密钥的根密钥。具体描述可以参考标准TS33.536章节中5.3.3.1.4.3的描述。
示例性地，第二终端设备向第一中继发送直连通信密钥鉴权(Direct Auth and Key Establishment)消息，触发第二终端设备和第一中继之间的鉴权流程。
可选地，第一中继可以确定Direct Auth and Key Establishment消息是发给自身的，并且第一中继在收到消息后会发起与第二终端设备进行鉴权和密钥生成流程。具体地，第一中继可以按照如下至少2种方式确定，一种方式是：Direct Auth and Key Establishment消息中包括指示信息，或指示信息随着Direct Auth and Key Establishment消息发送给第二终端设备(此时可以理解为指示信息在Direct Auth and Key Establishment消息外)，该指示信息用于指示鉴权和密钥分发是在第二终端设备和第一中继之间执行。比如，用一个比特位指示该消息是发给第一中继的，还是发给第一终端设备的。具体地，当比特位指示信息为“0”时，表示发给第一中继的，当是“1”时，则是发给第一终端设备的。另一种方式是：第一中继通过该Direct Auth and Key Establishment消息的格式确定鉴权和密钥分发是在第二终端设备和第一中继之间执行。比如，Direct Auth and Key Establishment作为一个container的一部分发给第一中继，则第一中继将container中的Direct Auth and Key Establishment消息发个第一终端设备，此时，第一中继可能不知道container中的内容，即不知道是Direct Auth and Key Establishment消息。也就是说，第一中继仅仅是看到container就转发了。再比如，Direct Auth and Key Establishment直接发送给了第一中继，那么第一中继自动判断这条消息是发给第一中继的，而不是发给第一终端设备的。
需要补充说明的是：如果安全终结点策略是标准规定好的，即标准规定了只能使用hop-by-hop或者End-to-End，那么第一中继不需要确定Direct Auth and Key Establishment消息是发给自身的，还是发给第一终端设备的。即在标准规定是hop-by-hop情况下，第一中继会知晓Direct Auth and Key Establishment消息是发给自身的，在End-to-End情况下，第一中继会知晓Direct Auth and Key Establishment消息是发给第一终端设备的。知晓方法不限制本申请实施例不限制需要说明的是，在第二终端设备的PC5控制面安全策略为“NOT NEEDED”状态的情况下，以及在第一中继的PC5控制面安全策略、第一终端设备的PC5控制面安全策略与第二终端设备的PC5控制面安全策略发生冲突的情况下，不会发起上述步骤404，且第二终端设备向至少一个中继回复失败消息，用于拒绝DCR流程的建立。
步骤405，第二终端设备确定第二PC5链路的PC5控制面安全保护方法，和选择第二PC5链路的PC5控制面安全算法。
此步骤可以发生在步骤403之后，步骤404之前。
具体地，第二终端设备可以按照如下方式中的至少一种方式确定第二PC5链路的PC5控制面安全保护方法：
方式一，第二终端设备根据第一中继的PC5控制面安全策略和第二终端设备的PC5控制面安全策略确定第二PC5链路的PC5控制面安全保护方法。具体地确定方法可以参考标准TS33.536章节中5.3.3.1.4.3的描述。
示例性地，第一中继的PC5控制面完整性保护为可选，第一中继的PC5控制面机密性保护为开启，第二终端设备PC5控制面完整性保护为开启，第二终端设备PC5控制面机密性保护为开启，则第二终端设备确定第二PC5链路的PC5控制面完整性保护为开启，第二PC5链路的PC5控制面机密性保护为开启。
方式二，第二终端设备除了根据第一中继的PC5控制面安全策略和第二终端设备的PC5控制面安全策略，还要结合第一终端设备的PC5控制面安全策略确定第二PC5链路的PC5控制面安全保护方法。这样，第一中继和第二终端设备之间的PC5控制面安全保护方法，和第一中继与第一终端设备之间的PC5控制面安全保护方法可以是相同的。
具体地，当其中一个控制面面完整性保护为REQUIRED，则控制面完整性保护确定为需要激活。当其中一个控制面机密性保护为REQUIRED，则控制面机密性保护确定为需要激活。其中一个控制面面完整性保护为NOT NEEDED，则控制面完整性保护确定为不需要激活。当其中一个控制面机密性保护为NOT NEEDED，则控制面机密性保护确定为不需要激活。当所有控制面面完整性保护为PREFERRED，则控制面完整性保护确定为可以激活，也可以不激活。当其中一个控制面机密性保护为PREFERRED，则控制面机密性保护确定可以激活，也可以不激活。
方式三，第二终端设备根据第一中继的PC5控制面安全策略和第二终端设备的PC5控制面安全策略，还可以结合第二终端设备的PC5用户面安全策略，确定PC5控制面安全保护方法。
示例性，如果第二终端设备确定第二终端设备的PC5用户面安全策略有“REQUIRED”状态，同时，第一中继的PC5控制面安全策略可以支持REQUIRED(比如为PREFEER，或者REQUIRED)，并且第二终端设备的PC5控制面安全策略可以支持REQUIRED(比如为PREFEER，或者REQUIRED)，则将第二PC5链路的PC5控制面安全策略确定为开启状态。具体地，如果第二终端设的PC5用户面完整性保护为REQUIRED，则第二终端设备将控制面完整性保护确定为开启。如果第二终端设的用户面完整性保护为PREFERRED，则控制面完整性保护的确定方法还需要参考第二终端设备的用户面机密性保护。即如果此时第二终端设备的用户面机密性保护为REQUIRED，则第一控制面完整性保护方法确定为开启,控制面机密性保护为REQUIRED；如果此时第二终端设备的用户面机密性保护为PREFERRED或者NOT NEEDED，则第二终端设备可以将控制面完整性保护确定为开启或者不开启，控制面机密性保护可以确定为开启或不开启。如果第二终端设的用户面完整性保护为NOT NEEDED，则控制面完整性保护的确定方法还需要参考第二终端设备的用户面机密性保护。即如果此时第二终端设备的用户面机密性保护为REQUIRED，则拒接连接建立；如果此时第二终端设备的用户面机密性保护为PREFERRED或者NOTE NEEDED，则第二终端设备可以将控制面完整性保护确定为开启或者不开启，将控制面机密性保护确定为开启或者不开启。
在确定了是否激活第二PC5链路的PC5控制面安全保护方法后，第二终端设备可以选择PC5控制面的安全算法。该安全算法包括机密性保护算法和/或完整性保护算法。如果确定第二PC5链路的PC5控制面完整性保护需要激活，则需要选择一个非空的PC5控制面完整性安全算法；如在确定第二PC5链路的PC5控制面完整性保护激活，且确定第二PC5链路的PC5控制面机密性保护需要激活的情况下，需要选择一个非空的PC5控制面机密性保护算法和非空的PC5控制面完整性保护算法；如果确定第二PC5链路的PC5控制面完整性保护不激活，则不需要选择PC5控制面完整性波保护算法。可选地，如果有安全算法策略，那么第二终端设备根据安全算法策略选择128bit算法还是256bit算法。具体选择方法可以参考标准TS33.536章节中5.3.3.1.4.3的描述。
步骤406，第二终端设备向第一中继发送第二PC5链路的PC5控制面安全算法。
在执行步骤406前，第二终端设备激活步骤405中确定的安全保护方法。具体地，如果PC5控制面完整性保护开启，则开始使用PC5控制面完整性保护算法和PC5控制面完性保护密钥对步骤406消息做完整性保护。如果PC5控制面机密性保护确定为开启，则开始使用选择的PC5控制面机密性保护算法和PC5控制面机密性密钥准备对收到的消息进行解机密性保护。其中，PC5控制面算法和PC5控制面密钥可以参考标准TS 33.536章节5.3.3.1.4.3中提到的相关控制面算法和控制面密钥。
确定PC5控制面安全算法的方法是：第二终端设备存储有控制面完整性保护算法优先级列表，第二终端设备可以从步骤402中携带的第一终端设备和/或第一中继的支持的控制面安全算法中选择一个优先级最高的同时支持的控制面安全算法。比如，如果第一终端设备支持NIA0(Nextgeneration Integrity Algorithm,下一代完整性保护算法)，NIA1，NIA2，NIA3第一中继支持NIA0，NIA2，NIA3第二终端设备的优先级列表为NIA1，NIA3，NIA2。在只考虑第一终端设备和第二终端设备的情况下，选择的控制面完整性保护算法为NIA1。在只考虑第一中继和第二终端设备的情况下，选择的控制面完整性保护算法为NIA3。在考虑第一中继、第一终端设备和第二终端设备的情况下，选择的控制面完整性保护算法为NIA2。再比如，如果第一终端设备支持NEA0(Nextgeneration EncryptionAlgorithm,下一代加密算法)，NEA1，NEA2，NEA3第一中继支持NEA0，NEA2，NEA3第二终端设备的优先级列表为NEA1，NEA3，NEA2。在只考虑第一终端设备和第二终端设备的情况下，选择的控制面完整性保护算法为NEA1。在只考虑第一中继和第二终端设备的情况下，选择的控制面完整性保护算法为NEA3。在考虑第一中继、第一终端设备和第二终端设备的情况下，选择的控制面完整性保护算法为NEA2。
示例性地，第二终端设备发送直连安全通信模式信令(direct security mode command，DSMC)消息至第一中继，该消息中携带第二终端设备确定第二PC5链路的控制面安全算法。具体携带方法可以参考标准TS33.536章节中5.3.3.1.4.3的描述。
步骤407，第一中继根据接收到的第二PC5链路的控制面安全算法，激活第二PC5链路的控制面安全。具体地，第一中继根据步骤406中携带的PC5控制面算法激活第二PC5链路的控制面安全保护。具体激活方法可以参考标准TS33.536章节中5.3.3.1.4.3的描述。
示例性地，如果第二PC5链路的控制面安全算法包括不为空完整性保护算法和为空的机密性保护算法，则第一中继开启第二PC5链路的控制面完整性保护，不开启第二PC5链路的控制面机密性保护。具体激活方法可以参考标准TS33.536章节中5.3.3.1.4.3的描述。
步骤408，第一中继与该第一终端设备进行鉴权流程。示例性地，第一中继向第一终 端设备发送Direct Auth and Key Establishment消息，发起鉴权和密钥生成流程，具体可以参考步骤404中的描述，在此不再重复赘述。
在一种可能的实施例中，可选地，在步骤408前，第一中继需要判断第一终端设备的控制面安全策略是不是可以被第一中继冲突，当不冲突时，第一中继执行下述步骤。否则，则释放连接。如果第一中继在步骤402中已经做出判断，则不需要再次执行这个判断过程。
步骤409，第一中继确定第一PC5链路的PC5控制面安全算法，以及激活第一PC5链路的控制面安全。
其中，第一PC5链路指的是第一终端设备和第一中继之间的PC5链路。
一种可能的实施例中，第一中继可以使用第一中继和第二终端设备之间的控制面安全保护方法，作为第一PC5链路的PC5控制面安全保护方法。具体地，第一中继可以根据第步骤407的决定结果，将决定结果用在第一PC5链路上。
另一种可能的实施例中，第一中继可以自己确定第一终端设备和第一中继之间的控制面安全保护方法，作为第一PC5链路的PC5控制面安全保护方法。该安全保护方法可能与第一中继和第二终端设备之间的控制面安全保护方法相同，也可能不同。即第一链路和第二链路是彼此独立的。
进一步地，可选地，第一中继在确定是否激活第一PC5链路的控制面安全保护方法前，第一中继校验该控制面安全保护方法是否与第一终端设备的PC5控制面安全策略冲突，如果冲突则释放连接，如果不冲突则将第一中继和第二终端设备之间的控制面安全保护方法确定为第一PC5链路的PC5控制面安全保护方法。
当确定了PC5控制面安全保护方法之后，进一步地，第一中继选择第一PC5链路的PC5控制面安全算法，以及激活第一PC5链路的控制面安全。方式一，第一中继可以确定第二终端设备所选择的控制面安全算法是否可以直接使用，如果可以直接使用的话，就将第二终端设备作为第一PC5链路的PC5控制面安全算法。如果不行，则再进行算法选择。进一步确定方法主要是看第二终端设备选择的算法是不是第一中继支持的优先级最高的，如果是，则确定可以使用。如果不是，则第一中继要选择UE-1支持的，同时第一中继优先级最高的安全算法(一个机密性保护算法和、或一个完整性保护算法)。方式二，第一中继按步骤406的描述确定第一PC5链路的安全算法。
步骤410，第一中继向第一终端设备发送第一PC5链路的控制面安全算法。
在步骤410之前，第一中继激活第一终端设备和第一中继之间的控制面安全保护。激活方法可以参考步骤406。
示例性地，第一中继发送Direct Security Mode Command消息给第一终端设备，该消息中携带第一PC5链路的控制面安全算法。
步骤411，第一终端设备根据接收到的控制面安全算法激活第一PC5链路的PC5控制面安全。
本申请实施例中，上述步骤401至步骤411是终端设备之间的PC5链路的控制面安全保护方法的确定过程，按照上述方法可以保证第一PC5链路和第二PC5链路的控制面安全的一致性，能够实现对于中继两侧的控制面安全保护的协同处理，可以使得中继两侧的链路要么均激活控制面完整性保护方法，要么均不激活控制面完整性保护方法，和/或，使得中继两侧的链路要么均激活控制面机密性保护方法，要么均不激活控制面机密性保护方法，从而使中继两侧的链路在安全保护处理方式上保持一致。以避免因第二PC5链路所使用的 控制面安全保护的优先级较高，导致第一PC5链路的控制面安全保护失败的问题，或者避免因第一PC5链路所使用的控制面安全保护的优先级较高，导致第二PC5链路的控制面安全保护失败的问题。
下述步骤412至步骤419为终端设备之间的PC5链路的用户面安全保护方法的确定过程。
步骤412，第一终端设备向第一中继发送第一PC5链路的DSMP消息。
示例性地，第一终端设备回复直连安全通信模式信令(direct security mode command，DSMC)消息给第一中继，该DSMP消息用于响应Direct Security Mode Command消息，该消息中可以携带第一终端设备的PC5用户面安全策略。
步骤413，第一中继发送第二PC5链路的DSMP消息给第二终端设备。
可选地，该第二PC5链路的DSMP消息中还可以携带第一中继的PC5用户面安全策略，或者第一中继还向第二终端设备发送第一中继的PC5用户面安全策略。也就是说，第二PC5链路的DSMP消息中携带第一终端的PC5用户面安全策略和第一中继的PC5用户面安全策略。
该第二PC5链路DSMP消息也可以是第一中继发送新的DSMP消息，该新的DSMP消息中携带第一中继的PC5用户面安全策略。
需要说明的是，一种可能实现方法是：第一中继将第一PC5链路的DSMP消息中的第一终端设备的PC5用户面安全策略替换成第一中继的PC5用户面安全策略。
步骤414，第二终端设备根据来自第一中继的PC5用户面安全策略和第二终端设备的PC5用户面安全策略，确定第二PC5链路的PC5用户面安全保护方法，并确定第二PC5链路的PC5用户面安全算法。
具体地，第二终端设备可以按照如下方式中的至少一种方式确定是否激活第二PC5链路的PC5用户面安全保护方法：
方式A，第二终端设备根据第一中继的PC5用户面安全策略和第二终端设备的PC5用户面安全策略，确定是否激活第二PC5链路的PC5用户面安全保护方法。具体携带方法可以参考标准TS33.536章节中5.3.3.1.4.2的描述。
方式B，第二终端设备除了根据第一中继的PC5用户面安全策略和第二终端设备的PC5用户面安全策略，还要结合第一终端设备的PC5用户面安全策略确定是否激活第二PC5链路的PC5用户面安全保护方法。这样，第一中继和第二终端设备之间的PC5用户面安全保护方法，和第一中继与第一终端设备之间的PC5用户面安全保护方法是相同的。具体地，如果有任意两个用户面机密性保护策略和、或用户面完整性保护策略是冲突的(一个是NOT NEEDED，一个是REQUIRED)，则需要拒绝连接。比如假设第一终端设备的用户面机密性策略是NOT NEEDED，但是第二中终端设备的用户面机密性保护策略是REQUIRED，则第二终端设备释放连接。当任意两个用户面机密性保护策略和、或用户面完整性保护策略均没有冲突的时，如果有REQUIRED，则开启REQUIRED对应的安全。比如，第一终端设备的用户面机密性策略是REQUIRED，或者第二中终端设备的用户面机密性保护策略是REQUIRED，则第二终端设备开启用户面机密性保护。如果第一终端设备的用户面机密性保护策略、第二终端设备的用户面机密性保护策略、第一中继的用户面安全策略都是PREFERRED的情况下，第二终端设备可以决定用户面机密性保护开启，也可以决定用户面机密性保护不开启。当任意两个用户面机密性保护策略和、或用户面完整性 保护策略均没有冲突的时，如果有NOT NEEDED，则不开启对应的安全。比如，第一终端设备的用户面机密性策略是NOT NEEDED，或者第二中终端设备的用户面机密性保护策略是NOT NEEDED，则第二终端设备不开启用户面机密性保护。进一步地，在激活了第二PC5链路控制面安全之后，可选地，用户面安全开启方法要参考激活了的第二PC5链路控制面安全保护方法。具体地，如果控制面机密性保护开启，则用户面机密性保护可以开启也可以不开启。如果控制面机密性保护不开启，则用户面机密性保护不开启。如果控制面完整性保护开启，则用户面完整性保护可以开启也可以不开启。如果控制面完整性保护不开启，则用户面完整性保护不开启。
在确定了第二PC5链路的PC5用户面安全保护方法后，第二终端设备可以确定PC5用户面的安全算法。一种可能的实现方式是：重用选择的PC5控制面安全算法为PC5用户面安全算法。另一种实现方式为：重新选择PC5用户面安全算法。该安全算法包括机密性保护算法和/或完整性保护算法。可选地，如果有安全算法策略，那么第二终端设备根据安全算法策略选择128bit算法还是256bit算法。
步骤415，第二终端设备向第一中继发送第一信息。
第一信息用于指示第二PC5链路的用户面安全保护方法。示例性地，第一信息为第二PC5链路的用户面安全激活指示。
具体地，第二终端设备发送直连通信接受(direct communication accept)消息至第一中继。该消息中携带该第二PC5链路的用户面安全激活指示。用户面安全激活指示的定义可以参考标准TS33.536章节中5.3.3.1.4.2的描述。
示例性地，若第二终端设备确定的第二PC5链路的用户面安全保护方法为第二PC5链路的用户面机密性保护不开启，第二PC5链路的用户面完整性保护开启，那么该用户面安全激活指示用于指示激活第二PC5链路的用户面完整性保护，不激活第二PC5链路用户面机密性保护。
步骤416，第一中继按照第一信息，激活第二PC5链路的用户面安全保护。
接续上例，第一中继收到用户面安全激活指示之后，根据用户名安全激活指示激活第一中继激活第二PC5链路的用户面完整性保护，不激活第一中继激活第二PC5链路的用户面机密性保护。
步骤417，第一中继向第一终端设备发送第二信息。
示例性地，第二信息用于指示第一PC5链路的用户面安全保护方法。
一种可能的情况下，该第二信息为第一信息，即第一中继向第一终端设备转发第一信息。
在另一种可能的情况下，第一中继根据第二PC5链路的用户面安全保护方法，确定第一PC5链路的PC5用户面安全保护方法，并生成第二信息，该第二信息和第一信息是相同的。
接续上例，第一中继确定第一PC5链路的PC5用户面安全保护方法也是开启用户面完整性保护，不开启用户面机密性保护。
步骤418，第一终端设备根据第二信息，激活第一PC5链路的用户面安全。
接续上例，若第一PC5链路的用户面安全激活指示第一PC5链路的用户面完整性保护开启，第一终端设备激活第一PC5链路的用户面完整性保护，第一PC5链路的用户面机密性保护不开启。
需要说明的是，上述步骤401至步骤411所示的控制面安全保护确定流程，与步骤412至步骤419所示的用户面安全保护确定流程可以是解耦的，即可以是分别单独执行的。
当上述两个流程单独执行时，可能存在第一中继在激活第一PC5链路的PC5控制面安全保护方法时没有依据第二终端设备所确定的第一PC5链路的PC5控制面安全保护方法，这时第一中继需要在确定第一PC5链路的用户面安全保护方法之前，先确定是否可以支持第二终端设备所确定的第二PC5链路的用户面安全保护方法，如果不能支持，则不满足用户面安全保护方法一致的要求，那么第一中继需要释放该连接，则直连通信链路建立失败。
图5为本申请实施例提供的一种安全通信方法流程示意图，该方法仍由第一通信装置执行，该方法可以包括如下步骤。
步骤501、第一终端设备广播第一直连通信请求(direct communication request，DCR)消息。
具体内容可以参见上述步骤401。
步骤502，至少一个中继接收到第一DCR消息后，向第二终端设备发送第二DCR消息。
具体内容可以参见上述步骤402。
步骤503，第二终端设备从至少一个中继确定用于建立第二PC5链路的第一中继。
具体内容可以参见上述步骤403。
在本申请实施例中，第一DCR消息包括第一终端设备的安全终结点策略为“end-to-end”安全，则本实施例的下文中，按照第二终端设备确定安全终结点位于第一终端设备展开论述。
步骤504a，在第二终端设备确定第一中继后，与该第一中继发起鉴权流程。
该步骤中，第二终端发送的消息中包括指示信息，该指示信息用于指示鉴权和密钥分发是在第二终端设备和第一终端设备之间执行，具体内容可以参见上述步骤404。
步骤504b，第一中继向第一终端设备发起鉴权流程。
本实施例中，第一终端设备和第一中继确定第二终端设备使用的安全终结点策略是End-to-End安全之后，之后的步骤中，第一中继接收来自第二终端设备的消息后，不再进行解析，而是直接发送至第一终端设备，这样做的好处是可以减小通信延时。
其中，第一中继识别End-to-End的方法可以参考步骤404的相关描述。
步骤505，第二终端设备确定第一终端设备和第二终端设备之间的PC5链路的PC5控制面安全保护方法，和选择所述第一终端设备和所述第二终端设备之间的PC5链路的PC5控制面安全算法。
具体地，第二终端设备根据第一终端设备的控制面安全策略和第二终端设备的控制面安全策略，确定第一终端设备和第一终端设备之间的PC5链路的PC5控制面安全保护方法。示例性，第一终端设备的PC5控制面完整性保护为REQUIRED，第一终端设备的PC5控制面机密性保护为REQUIRED，第二终端设备的PC5控制面完整性保护为REQUIRED，第二终端设备的PC5控制面机密性保护为NOT NEEDED，则第二终端设备确定开启第一终端设备和第二终端设备之间的PC5链路的PC5控制面安全完整性保护，不开启第一终端设备和第二终端设备之间的PC5链路的PC5控制面安全机密性保护。
在一种可能的实施例中，第二终端设备还可以根据第一终端设备的用户面安全策略和 第二终端设备的用户面安全策略，以及第一终端设备的控制面安全算法和第二终端设备的控制面安全算法，确定第一终端设备和第一终端设备之间的PC5链路的PC5控制面安全算法。
步骤506，第二终端设备向第一终端设备发送选择的PC5控制面安全算法。
所述PC5控制面安全算法用于第一终端设备和第二终端设备保护第一终端设备和第二终端设备之间的PC5链路。
示例性地，第二终端设备发送直连安全通信模式信令(direct security mode command，DSMC)消息至第一终端设备，该消息中携带第二终端设备确定第二PC5链路的控制面安全算法。
步骤507，第一终端设备根据接收到的所述PC5链路的控制面安全算法，激活第一终端设备和所述第二终端设备之间的PC5链路的PC5控制面安全。
本申请实施例中，上述步骤501至步骤508是终端设备之间的PC5链路的控制面安全保护方法的确定过程，按照上述方法可以确定第一终端设备和第二终端设备之间PC5链路的控制面安全保护方法，能够实现各个设备在控制面安全保护的处理方式上保持一致。
下述步骤508至步骤511为终端设备之间的PC5链路的用户面安全保护方法的确定过程。
步骤508，第一终端设备向第二终端设备发送第一DSMP消息。
示例性地，第一终端设备发送第一直连安全通信模式信令(direct security mode complete，DSMP)消息给第二终端设备，该第一DSMP消息用于响应Direct Security Mode Command消息，该消息中可以携带第一终端设备的PC5用户面安全策略。
具体内容可以参见上述步骤412。
步骤509，第二终端设备根据来自第一终端设备的PC5用户面安全策略和第二终端设备的PC5用户面安全策略，确定第一终端设备和第二终端设备之间的PC5链路的PC5用户面安全保护方法。
具体地，第二终端设备根据第一终端设备的用户面安全策略和第二终端设备的用户面安全策略，确定第一终端设备和第一终端设备之间的PC5链路的PC5用户面安全保护方法。示例性，第一终端设备的PC5用户面完整性保护为REQUIRED，第一终端设备的PC5用户面机密性保护为REQUIRED，第二终端设备的PC5用户面完整性保护为REQUIRED-，第二终端设备的PC5用户面机密性保护为NOT NEEDED，则第二终端设备确定开启第一终端设备和第二终端设备之间的PC5链路的PC5用户面安全完整性保护，不开启第一终端设备和第二终端设备之间的PC5链路的PC5用户面安全机密性保护。
在确定了第二PC5链路的PC5用户面安全保护方法后，第二终端设备可以选择PC5用户面的安全算法。该安全算法包括机密性保护算法和/或完整性保护算法。可选地，如果有安全算法策略，那么第二终端设备根据安全算法策略选择128bit算法还是256bit算法。
步骤510，第二终端设备向第一终端设备发送第三信息。
示例性地，该第三信息包括该第一终端设备和第二终端设备之间的PC5链路的用户面安全激活指示信息。所述用户面安全激活指示信息用于指示第一终端设备和第二终端设备之间的PC5链路的用户面安全保护方法。
示例性地，第二终端设备发送直连通信接受(direct communication accept)消息至第一终端设备。该消息中携带该用户面安全激活指示。
步骤511，第一终端设备确定第一终端设备和第二终端设备之间的PC5链路的用户面安全保护方法，并激活第一终端设备和第二终端之间的PC5链路的用户面安全。
本申请实施例中，上述步骤509至步骤512是终端设备之间的PC5链路的用户面安全保护方法的确定过程，按照上述方法可以确定第一终端设备和第二终端设备之间PC5链路的用户面安全保护方法，能够实现各个设备在用户面安全保护的处理方式上保持一致。
图6为本申请实施例提供的一种安全通信方法流程示意图，该方法可以包括如下步骤。
步骤601、第一终端设备广播直连通信请求(direct communication request，DCR)。
具体内容可以参见上述步骤401。
需要说明的是，本实施例采用hop-by-hop安全，因此安全终结点的位置位于中继，本实施例下文中是按照安全终结点的位置位于中继的情况下进行论述的。
步骤602a，每个接收到DCR消息的中继，均根据第一终端设备的PC5控制面安全策略和中继自身的PC5控制面安全策略，确定出第一PC5链路PC5控制面安全保护方法。
具体地，如果第一终端设备和中继的PC5控制面完整性保护有REQUIRED的，则确定开启PC5控制面完整性保护。如果第一终端设备和中继的PC5控制面完整性保护有NOT NEEDED的，则确定不开启PC5控制完整性保护。如果第一终端设备和中继的PC5控制面机密性保护有REQUIRED的，则确定开启PC5控制面机密性保护。如果第一终端设备和中继的PC5控制面机密性保护有NOT NEEDED的，则确定不开启PC5控制面机密性保护。如果第一终端设备和中继的PC5控制面完整性保护都是PREFERRED的，则可以确定开启PC5控制面完整性保护，也可以确定不开启控制面完整性保护。如果第一终端设备和中继的PC5控制面机密性保护都是PREFERRED的，则可以确定开启PC5控制面机密性保护，也可以确定不开启控制面机密性保护。
具体地方法可以参考标准TS33.5365.3.3.1.4.3的描述。
具体地，各个中继都可以按照上述步骤406确定第一PC5链路PC5控制面安全保护方法。
步骤602b，每个接收到第一DCR消息的中继，均向第二终端设备发送第二DCR消息，其中，所述第二DCR消息包括自身确定的第一PC5链路PC5控制面安全保护方法。
一种可能的实施例中，每个中继自身确定的第一PC5链路的PC5控制面安全保护方法可以被赋予安全策略的格式，然后每个中继可以使用自身确定的第一PC5链路的PC5控制面安全保护方法替代DCR消息中第一终端设备的PC5控制面安全策略。具体地，如果确定控制面完整性保护开启，则传递控制面完整性保护为REQUIRED的PC5控制面安全策略，如果控制面完整性保护不开启，则传递控制面完整性保护为NOT NEEDED的PC5控制面安全策略。如果确定控制面机密性保护开启，则传递控制面机密性保护为REQUIRED的PC5控制面安全策略，如果控制面机密性保护不开启，则传递控制面机密性保护为NOT NEEDED的PC5控制面安全策略。示例性地，第一终端设备在第一DCR消息中携带的是PC5控制面机密性保护为“PREFERRED”状态，PC5控制面完整性保护为“PREFERRED”状态。第一中继根据第一中继的PC5控制面安全策略和第一终端设备的PC5控制面安全策略，确定第二PC5链路的控制面完整性保护为“REQUIRED”状态，控制面机密性保护为“REQUIRED”状态。那么第一中继可以将第二DCR消息中的第一终端设备的PC5控制面安全策略替换为控制面机密性保护为“REQUIRED”状态，控制面完整性保护为 “REQUIRED”状态。
在另一种可能的实施例中，每个中继发送的DCR消息中还包括指示消息，该指示信息用于指示安全终结点的位置位于中继。
一种可能的实施例中，每个中继自身确定的第一PC5链路的PC5控制面安全保护方法可以被赋予指示信息格式或字符串格式。比如，“00”表示控制面机密性保护不开启，控制面完整性保护不开启，“01”表示控制面机密性保护不开启，控制面完整性保护开启；或者“enabled，enabled”指示信息。比如传递“enabled，disabled”则代表开启控制面完整性保护，不开启控制面机密性保护第二终端设备则可以根据收到的DCR消息，确定中继所选择的或者第二终端设备自身可以使用的PC5控制面安全策略。
在一种可选的方式中，第二DCR消息在携带自身确定的第一PC5链路的PC5控制面安全保护方法的同时，也可以按照步骤402一样携带至少一种PC5安全算法策略。
步骤603，第二终端设备从至少一个中继选择为第一终端服务的中继。
需要说明的是，本实施例中，该步骤403是可选的步骤。一种可能的情况下，在只有一个中继向第二终端设备转发DCR消息时，上述步骤403可以不用执行。这时，第二终端设备只需要在判断该中继是否支持该业务，若是，则确定该中继为第一终端服务的中继。比如，第二终端设备根据是否对消息中携带的应用信息感兴趣进行判断。
另一种可能的情况下，在有两个以上的中继向第二终端设备发送第二DCR消息时，第二终端设备根据收到的第一PC5链路的PC5控制面安全保护方法，确定第二终端设备支持哪个中继所述确定的第一PC5链路的控制面安全保护方法，第二终端设备从中选择一个中继作为目标中继，例如选择第一中继作为目标中继。
其中，步骤604至步骤611同上述步骤404至步骤411，在此不再重复赘述。
需要说明的是，在步骤605中，第二终端设备根据步骤602b中携带的中继自身确定的第一PC5链路的PC5控制面安全保护方法，和第二终端设备的PC5控制面安全保护策略，确定第二PC5链路的PC5控制面安全保护方法。具体地，如果以安全策略的形式传递，则第二终端设备根据第二DCR消息中携带的安全策略确定第二PC5链路的PC5控制面安全保护方法。如果以指示信息的方式传递，则第二终端设备根据指示信息确定第二PC5链路的PC5控制面安全策略。
在第二终端设备确定第二PC5链路的安全策略后，在发送步骤606前，激活第二PC5链路的PC5控制面安全。
本申请实施例中，上述步骤601至步骤611是终端设备之间的PC5链路的控制面安全保护方法的确定过程，按照上述方法可以保证第一PC5链路和第二PC5链路的控制面安全的一致性，能够实现对于中继两侧的控制面安全保护的协同处理，可以使得中继两侧的链路要么均激活控制面完整性保护方法，要么均不激活控制面完整性保护方法，和/或，使得中继两侧的链路要么均激活控制面机密性保护方法，要么均不激活控制面机密性保护方法，从而使中继两侧的链路在安全保护处理方式上保持一致。以避免因第二PC5链路所使用的控制面安全保护的优先级较高，导致第一PC5链路的控制面安全保护失败的问题，或者避免因第一PC5链路所使用的控制面安全保护的优先级较高，导致第二PC5链路的控制面安全保护失败的问题。
下述步骤612至步骤618为终端设备之间的PC5链路的用户面安全的确定过程。
步骤612，第一终端设备向第一中继发送第一PC5链路的DSMP消息。
示例性地，第一终端设备回复直连安全通信模式信令(direct security mode complete，DSMP)消息给第一中继，该DSMP消息用于响应Direct Security Mode Command消息，该消息中可以携带第一终端设备的PC5用户面安全策略。
步骤613，第一中继根据第一终端设备的PC5用户面安全策略和第一中继自身的PC5用户面安全策略，确定出第一PC5链路PC5用户面安全保护方法。
步骤614，第一中继发送第二PC5链路的DSMP消息，该消息包括第一中继确定的第一PC5链路的PC5用户面安全保护方法。具体地，用户面安全保护方法的传递方法可以参考步骤602b的相关描述。
步骤615，第二终端设备确定第二PC5链路的PC5用户面安全保护方法。
第二终端设备根据中继自身确定的第一PC5链路的PC5用户面安全保护方法和第二终端设备的PC5用户面安全策略，确定第二PC5链路的PC5用户面安全保护方法。具体地，如果以安全策略的形式传递，则第二终端设备根据第二DCR消息中携带的安全策略确定第二PC5链路的PC5用户面安全保护方法。如果以指示信息的方式传递，则第二终端设备根据指示信息确定第二PC5链路的PC5用户面安全保护方法。
步骤617至步骤619同上述步骤417至步骤419，在此不再重复赘述。
可见，本申请实施例中，是由中继确定第一终端设备和第二终端设备之间的PC5链路的控制面安全性和用户面安全。按照上述方法可以保证第一终端设备和第二终端设备之间PC5链路的控制面/用户面安全的一致性，能够实现对于中继两侧的控制面/用户面安全保护的协同处理，可以使得中继两侧的链路要么均激活控制面/用户面完整性保护方法，要么均不激活控制面/用户面完整性保护方法，和/或，使得中继两侧的链路要么均激活控制面/用户面机密性保护方法，要么均不激活控制面/用户面机密性保护方法，从而使中继两侧的链路在安全保护处理方式上保持一致。
针对于上述实施例可以分别在不同场景中单独实施，或者也可以在同一场景中结合实施，又或者，不同实施例中所涉及的不同方案也可以结合实施，具体不做限定。
本申请实施例中所描述的各个流程图的步骤编号仅为执行流程的一种示例，并不构成对步骤执行的先后顺序的限制，本申请实施例中相互之间没有时序依赖关系的步骤之间没有严格的执行顺序。
上述本申请提供的实施例中，从终端作为执行主体的角度对本申请实施例提供的安全通信方法进行了介绍。为了实现上述本申请实施例提供的安全通信方法中的各功能，终端可以包括硬件结构和/或软件模块，以硬件结构、软件模块、或硬件结构加软件模块的形式来实现上述各功能。上述各功能中的某个功能以硬件结构、软件模块、还是硬件结构加软件模块的方式来执行，取决于技术方案的特定应用和设计约束条件。
与上述实施例的构思相同，本申请实施例还提供一种通信装置700，该通信装置700用于实现上述方法中第一终端设备、第二终端设备和中继的功能。示例地，该第一通信装置700可以是第一终端设备，也可以是第一终端设备中的装置。该装置可以为芯片系统。本申请实施例中，芯片系统可以由芯片构成，也可以包含芯片和其他分立器件。一示例中，如图7所示，通信装置700包括处理单元701和收发单元702。
针对上述图4所示的发明构思，该通信装置700用于实现上述方法中第二终端设备的功能：
收发单元702用于接收来自中继的关于第一终端设备的第一请求消息；所述第一请求消息包括所述第一终端设备的PC5用户面安全策略和所述中继的PC5用户面安全策略。
处理单元701，用于根据所述第二终端设备的PC5用户面安全策略、所述第一终端设备的PC5用户面安全策略、所述中继的PC5用户面安全策略，确定第一信息；
所述收发单元702，还用于向所述中继发送所述第一信息，所述第一信息用于指示第一PC5链路的用户面安全保护方法和第二PC5链路的用户面安全保护方法；其中，所述第一PC5链路的用户面安全保护方法和第二PC5链路的用户面安全保护方法相同；
其中，所述第一PC5链路为所述中继与所述第一终端设备之间的PC5链路；所述第二PC5链路为所述中继与所述第二终端设备之间的PC5链路。
在一种实施例中，所述第一信息用于指示第一PC5链路的用户面安全保护方法和第二PC5链路的用户面安全保护方法，包括：
所述第一信息用于指示：所述第一PC5链路的用户面完整性保护和所述第二PC5链路的用户面完整性保护均开启或均不开启，和/或，所述第一PC5链路的用户面机密性保护和所述第二PC5链路的用户面机密性保护均开启或均不开启。
在一种实施例中，所述收发单元702，还用于接收来自中继的关于所述第一终端设备的第二请求消息，所述第二请求消息包括所述第一终端设备的PC5控制面安全策略所述中继的PC5控制面安全策略；
所述处理单元701，还用于根据所述第二终端设备的PC5控制面安全策略、所述第一终端设备的PC5控制面安全策略和所述中继的PC5控制面安全策略，确定第二PC5链路的控制面安全算法；
所述收发单元702，还用于向所述中继发送所述第二PC5链路的控制面安全算法，所述控制面安全算法用于指示所述第二PC5链路的控制面安全和所述第一PC5链路的控制面安全，其中，所述第一PC5链路的控制面安全保护方法和第二PC5链路上激活的控制面安全保护方法相同。
在一些实施例中，所述第二请求消息中还包括安全终结点策略的指示，所述安全终结点策略的指示用于指示安全终结点位于所述中继上。
在一些实施例中，述控制面安全算法用于指示所述第二PC5链路的控制面安全保护方法和所述第一PC5链路的控制面安全保护方法，包括
所述控制面安全算法用于指示：所述第一PC5链路的控制面完整性保护和所述第二PC5链路的控制面完整性保护均开启或均不开启，和/或，所述第一PC5链路的控制面机密性保护和所述第二PC5链路的控制面机密性保护均开启或均不开启。
在一些实施例中，所述处理单元701根据所述第二终端设备的PC5用户面安全策略、所述第一终端设备的PC5用户面安全策略和所述中继的PC5用户面安全策略，确定第一信息，具体用于：
根据所述第二终端设备的PC5用户面安全策略、所述第一终端设备的PC5用户面安全策略和所述中继的PC5用户面安全策略，以及所述第二PC5链路的控制面安全算法，确定所述第一信息；
其中，所述第二PC5链路的用户面安全保护方法的安全等级不高于所述第二PC5链路的控制面安全保护方法的安全等级，所述第一PC5链路的用户面安全保护方法的安全等级不高于所述第一PC5链路的控制面安全保护方法的安全等级。
在一些实施例中，所述第二PC5链路的用户面安全保护方法不高于所述第二PC5链路的控制面安全保护方法，所述第一PC5链路的用户面安全保护方法的安全等级不高于所述第一PC5链路的控制面安全保护方法，包括：
当第三PC5链路的控制面机密性保护开启，则所述第三PC5链路的用户面机密性保护开启或不开启；
当所述第三PC5链路的控制面机密性保护不开启，则所述第三PC5链路的用户面机密性保护不开启；
当所述第三PC5链路的控制面完整性保护开启，则所述第三PC5链路的用户面完整性保护开启或不开启；
当所述第三PC5链路的控制面完整性保护不开启，则所述第三PC5链路的用户面完整性保护不开启；
其中，所述第三PC5链路为所述第二PC5链路或者所述第一PC5链路。
关于处理单元701、收发单元702的具体执行过程和有益效果，可参见上述图4所示的方法实施例中的记载。
针对上述图6所示的发明构思，该通信装置700用于实现上述方法中第二终端设备的功能：
收发单元702用于请求包括安全终结点策略的指示，所述安全终结点策略的指示用于指示安全终结点位于中继上；
收发单元702，用于接收来自所述至少一个中继所确定的第一PC5链路的PC5控制面安全保护方法和第二PC5链路的PC5控制面安全保护方法；
处理单元701，用于根据所述第二终端设备的PC5控制面安全策略，以及所述至少一个中继所确定的第一PC5链路的PC5控制面安全保护方法和第二PC5链路的PC5控制面安全保护方法，确定目标中继；
所述收发单元702，还用于接收来自所述目标中继所确定的第一PC5链路的PC5用户面安全保护方法和第二PC5链路的PC5用户面安全保护方法；
所述处理单元701，还用于根据来自所述目标中继的第一PC5链路的PC5用户面安全保护反复，和所述第二终端设备的PC用户面安全保护方法，确定第一信息；
所述收发单元702，还用于所述第二终端设备向所述中继发送所述第一信息，所述第一信息用于指示第一PC5链路的用户面安全保护方法和第二PC5链路的用户面安全保护方法；其中，所述第一PC5链路的用户面安全保护方法和第二PC5链路的用户面安全保护方法相同；
其中，所述第一PC5链路为所述中继与所述第一终端设备之间的PC5链路；所述第二PC5链路为所述中继与所述第二终端设备之间的PC5链路。
在一些实施例中，所述第一信息用于指示第一PC5链路的用户面安全保护方法和第二PC5链路的用户面安全保护方法，包括：
所述第一信息用于指示：所述第一PC5链路的用户面完整性保护和所述第二PC5链路的用户面完整性保护均开启或均不开启，和/或，所述第一PC5链路的用户面机密性保护和所述第二PC5链路的用户面机密性保护均开启或均不开启。
在一些实施例中，所述处理单元，还用于根据来自所述目标中继所确定的第一PC5链 路的PC5用户面安全保护方法和第二PC5链路的PC5用户面安全保护方法，确定所述第二PC5链路的控制面安全算法，；
所述收发单元702，还用于向所述中继发送第二PC5链路的控制面安全算法，所述第二PC5链路的控制面安全算法用于指示所述第二PC5链路的控制面安全和所述第一PC5链路的控制面安全。
在一些实施例中，所述第二PC5链路的控制面安全算法用于指示所述第二PC5链路的控制面安全和所述第一PC5链路的控制面安全，包括：
所述第二PC5链路的控制面安全算法用于指示：所述第一PC5链路的控制面完整性保护和所述第二PC5链路的控制面完整性保护均开启或均不开启，和/或，所述第一PC5链路的控制面机密性保护和所述第二PC5链路的控制面机密性保护均开启或均不开启。
在一些实施例中，所述处理单元701根据来自所述目标中继的第一PC5链路的PC5用户面安全保护方法，和所述第二终端设备的PC用户面安全策略，确定第一信息，具体用于：
根据来自所述目标中继的第一PC5链路的PC5用户面安全保护方法，以及所述第二PC5链路的控制面安全算法，确定所述第一信息；
其中，所述第二PC5链路的用户面安全保护方法的安全等级不高于所述第二PC5链路的控制面安全保护方法的安全等级，所述第一PC5链路的用户面安全保护方法的安全等级不高于所述第一PC5链路的控制面安全保护方法的安全等级。
在一些实施例中，所述第二PC5链路的用户面安全保护方法不高于所述第二PC5链路的控制面安全，所述第一PC5链路的用户面安全保护方法的安全等级不高于所述第一PC5链路的控制面安全保护方法，包括：
当第三PC5链路的控制面机密性保护开启，则所述第三PC5链路的用户面机密性保护开启或不开启；
当所述第三PC5链路的控制面机密性保护不开启，则所述第三PC5链路的用户面机密性保护不开启；
当所述第三PC5链路的控制面完整性保护开启，则所述第三PC5链路的用户面完整性保护开启或不开启；
当所述第三PC5链路的控制面完整性保护不开启，则所述第三PC5链路的用户面完整性保护不开启；
其中，所述第三PC5链路为所述第二PC5链路或者所述第一PC5链路。
关于处理单元701、收发单元702的具体执行过程和有益效果，可参见上述图6所示的方法实施例中的记载。
针对上述图4至图6所示的发明构思，该通信装置700用于实现上述方法中第二终端设备的功能：
收发单元702，用于通过至少一个中继接收来自第一终端设备的直连通信请求；
处理单元701，用于根据安全策略辅助信息，从所述至少一个中继中确定目标中继；
收发单元701，用于通过所述目标中继与所述第一终端设备通信。
在一些实施例中，所述安全策略辅助信息包括所述至少一个中继的PC控制面安全策略；
所述处理单元701，根据安全策略辅助信息，从所述至少一个中继中确定目标中继，具体用于：
从所述至少一个中继中选择一个包括可选的PC5控制面安全策略的目标中继。
在一些实施例中，所述安全策略辅助信息包括所述至少一个中继的PC控制面安全策略，以及所述第二终端设备的PC5控制面安全策略；
所述第二终端设备根据安全策略辅助信息，从所述至少一个中继中确定目标中继，包括：
所述处理单元701，具体用于根据从所述至少一个中继中，选择一个中继的PC控制面安全策略与所述第二终端设备的PC5控制面安全策略不冲突的目标中继。
在一些实施例中，所述安全策略辅助信息包括所述至少一个中继的PC控制面安全策略，以及所述第二终端设备的PC5控制面安全策略；
所述处理单元701，具体用于所述第二终端设备根据安全策略辅助信息，从所述至少一个中继中，选择一个中继的PC用户面安全保护方法的安全等级不高于所述第二终端设备的PC控制面安全保护方法的安全等级的目标中继。
在一些实施例中所述安全策略辅助信息是策略控制功能网元预先配置的。
关于处理单元701、收发单元702的具体执行过程和有益效果，可参见上述图6所示的方法实施例中的记载。
针对上述图4所示的发明构思，该通信装置700用于实现上述方法中中继的功能：
收发单元702，用于向第二终端设备发送关于第一终端设备的第一请求消息；所述第一请求消息包括所述第一终端设备的PC5用户面安全策略和所述中继的PC5用户面安全策略；
收发单元702，用于接收来自第二终端设备的第一信息，所述第一信息用于指示第一PC5链路的用户面安全保护方法和第二PC5链路的用户面安全保护方法；其中，所述第一PC5链路的用户面安全保护方法和第二PC5链路的用户面安全保护方法相同；
处理单元701，用于根据所述第一信息，激活所述第二PC5链路的用户面安全保护方法，以及激活第一PC5链路的用户面安全保护方法；
其中，所述第一PC5链路为所述中继与第一终端设备之间的PC5链路，所述第二PC5链路为所述中继与所述第二终端设备之间的PC5链路。
在一些实施例中，所述收发单元702，还用于向所述第二终端设备发送所述第一终端设备的控制面安全策略和所述中继的控制面安全策略，第一终端设备的控制面安全策略和所述中继的控制面安全策略用于确定所述第二PC5链路的控制面安全算法；
所述收发单元702，还用于接收来自第二终端设备的所述第二PC5链路的控制面安全算法，所述控制面安全算法用于指示所述第二PC5链路的控制面安全保护方法和所述第一PC5链路的控制面安全保护方法；
所述处理单元701，还用于根据所述第二PC5链路的控制面安全算法，激活所述第二PC5链路的控制面安全保护方法，以及所述第一PC5链路的控制面安全保护方法，其中，所述第一PC5链路的控制面安全保护方法和第二PC5链路上激活的控制面安全保护方法相同。
在一些实施例中，所述中继的PC5控制面安全保护方法的安全等级不高于所述第二链 路的PC5用户面安全保护方法的安全等级。
在一些实施例中，所述第一PC5链路的用户面安全保护方法的安全等级不高于所述第一PC5链路的控制面安全保护方法的安全等级；第二PC5链路的用户面安全保护方法的安全等级不高于所述第二PC5链路的控制面安全保护方法的安全等级。
针对上述图6所示的发明构思，该通信装置700用于实现上述方法中中继的功能：
收发单元702，用于向第二终端设备发送自第一终端设备的直连通信请求；所述直连通信请求包括安全终结点策略的指示，所述安全终结点策略的指示用于指示安全终结点位于中继上；
处理单元701，用于根据所述中继的PC5用户面安全策略和所述第一终端设备的PC用户面安全策略，确定第一PC5链路的PC5用户面安全保护方法；
收发单元702，还用于向所述第二终端设备，发送所述第一PC5链路的PC5用户面安全保护方法；
收发单元702，还用于接收来自所述第二终端设备的第一信息，所述第一信息用于指示第一PC5链路的用户面安全保护方法和第二PC5链路的用户面安全保护方法；
所述处理单元701，还用于根据所述第一信息，激活所述第二PC5链路的用户面安全保护方法，以及激活第一PC5链路的用户面安全保护方法；所述第二PC5链路的用户面安全保护方法和所述第一PC5链路的用户面安全保护方法相同；
其中，所述第一PC5链路为所述中继与所述第一终端设备之间的PC5链路；所述第二PC5链路为所述中继与所述第二终端设备之间的PC5链路。
在一些实施例中，所述第一信息用于指示第一PC5链路的用户面安全保护方法和第二PC5链路的用户面安全保护方法，包括：
所述第一信息用于指示：所述第一PC5链路的用户面完整性保护和所述第二PC5链路的用户面完整性保护均开启或均不开启，和/或，所述第一PC5链路的用户面机密性保护和所述第二PC5链路的用户面机密性保护均开启或均不开启。
在一些实施例中，所述收发单元702，还用于接收来自所述第一终端设备的第二请求消息，所述第二请求消息包括所述第一终端设备的PC5控制面安全策略所述中继的PC5控制面安全策略；
所述处理单元701，还用于根据所述中继的PC5控制面安全策略和所述第一终端设备的PC5控制面安全策略，确定所述第一PC5链路的PC5控制面安全保护方法和所述第二PC5链路的PC5控制面安全保护方法；
所述收发单元702，还用于向所述第二终端设备发送所述第一PC5链路的PC5控制面安全保护方法和所述第二PC5链路的PC5控制面安全保护方法；
所述收发单元702，还用于接收来自所述第二终端设备的所述第二PC5链路的控制面安全算法，所述控制面安全算法用于指示所述第二PC5链路的控制面安全和所述第一PC5链路的控制面安全，所述控制面安全算法是根据所述第一PC5链路的PC5控制面安全保护方法和所述第二PC5链路的PC5控制面安全保护方法确定的；
所述处理单元701，还用于根据所述第二PC5链路的控制面安全算法，激活所述第二PC5链路的控制面安全保护方法和所述第一PC5链路的控制面安全保护方法。
在一些实施例中，所述控制面安全算法用于指示所述第二PC5链路的控制面安全和所述第一PC5链路的控制面安全保护方法，包括：
所述控制面安全算法用于指示：所述第一PC5链路的控制面完整性保护和所述第二PC5链路的控制面完整性保护均开启或均不开启，和/或，所述第一PC5链路的控制面机密性保护和所述第二PC5链路的控制面机密性保护均开启或均不开启。
在一些实施例中，所述第二PC5链路的用户面安全保护方法的安全等级不高于所述第二PC5链路的控制面安全保护方法的安全等级，所述第一PC5链路的用户面安全保护方法的安全等级不高于所述第一PC5链路的控制面安全保护方法的安全等级。
本申请实施例中对模块的划分是示意性的，仅仅为一种逻辑功能划分，实际实现时可以有另外的划分方式，另外，在本申请各个实施例中的各功能模块可以集成在一个处理器中，也可以是单独物理存在，也可以两个或两个以上模块集成在一个模块中。上述集成的模块既可以采用硬件的形式实现，也可以采用软件功能模块的形式实现。
又一示例中，如图8所示，该通信装置700包括至少一个处理器810和存储器820。其中，存储器820中存储有计算机程序。存储器820和处理器810耦合。本申请实施例中的耦合是装置、单元或模块之间的间隔耦合或通信连接，可以是电性，机械或其它的形式，用于装置、单元或模块之间的信息交互。作为另一种实现，存储器820还可以位于通信装置700之外。处理器810可以和存储器820协同操作。处理器810可以调用存储器820中存储的计算机程序。所述至少一个存储器中的至少一个可以包括于处理器中。
在一些实施例中，通信装置700还可以包括通信接口830，用于通过传输介质和其它设备进行通信，从而用于通信装置700中的装置可以和其它设备进行通信。示例性地，通信接口830可以是收发器、电路、总线、模块或其它类型的通信接口，该其它设备可以是其它终端。处理器810利用通信接口830收发信息，并用于实现上述实施例中的方法。示例性的，通信接口830用于接收资源指示信息。又示例性的，通信接口830用于发送数据。
在本申请实施例中，处理器可以是通用处理器、数字信号处理器、专用集成电路、现场可编程门阵列或者其他可编程逻辑器件、分立门或者晶体管逻辑器件、分立硬件组件，可以实现或者执行本申请实施例中的公开的各方法、步骤及逻辑框图。通用处理器可以是微处理器或者任何常规的处理器等。结合本申请实施例所公开的方法的步骤可以直接体现为硬件处理器执行完成，或者用处理器中的硬件及软件模块组合执行完成。
在本申请实施例中，存储器可以是非易失性存储器，比如硬盘(hard disk drive，HDD)或固态硬盘(solid-state drive，SSD)等，还可以是易失性存储器(volatile memory)，例如随机存取存储器(random-access memory，RAM)。存储器是能够用于携带或存储具有指令或数据结构形式的期望的程序代码并能够由计算机存取的任何其他介质，但不限于此。本申请实施例中的存储器还可以是电路或者其它任意能够实现存储功能的装置，用于存储计算机程序和/或数据。
本申请实施例提供的方法中，可以全部或部分地通过软件、硬件、固件或者其任意组合来实现。当使用软件实现时，可以全部或部分地以计算机程序产品的形式实现。所述计算机程序产品包括一个或多个计算机指令。在计算机上加载和执行所述计算机计算机程序时，全部或部分地产生按照本发明实施例所述的流程或功能。所述计算机可以是通用计算机、专用计算机、计算机网络、网络设备、用户设备或者其他可编程装置。所述计算机指令可以存储在计算机可读存储介质中，或者从一个计算机可读存储介质向另一个计算机可 读存储介质传输，例如，所述计算机指令可以从一个网站站点、计算机、服务器或数据中心通过有线(例如同轴电缆、光纤、数字用户线(digital subscriber line，简称DSL))或无线(例如红外、无线、微波等)方式向另一个网站站点、计算机、服务器或数据中心进行传输。所述计算机可读存储介质可以是计算机可以存取的任何介质或者是包含一个或多个介质集成的服务器、数据中心等数据存储设备。所述介质可以是磁性介质(例如，软盘、硬盘、磁带)、光介质(例如，数字视频光盘(digital video disc，简称DVD))、或者半导体介质(例如，SSD)等。
显然，本领域的技术人员可以对本申请进行各种改动和变型而不脱离本申请的范围。这样，倘若本申请的这些修改和变型属于本申请权利要求及其等同技术的范围之内，则本申请也意图包含这些改动和变型在内。

Claims (18)

  1. 一种安全通信方法，其特征在于，包括：
    接收来自中继的关于第一终端设备的第一请求消息；所述第一请求消息包括所述第一终端设备的PC5用户面安全策略和所述中继的PC5用户面安全策略；
    根据第二终端设备的PC5用户面安全策略、所述第一终端设备的PC5用户面安全策略、所述中继的PC5用户面安全策略，确定第一信息；
    向所述中继发送所述第一信息，所述第一信息用于指示第一PC5链路的用户面安全保护方法和第二PC5链路的用户面安全保护方法；其中，所述第一PC5链路的用户面安全保护方法和第二PC5链路的用户面安全保护方法相同；
    其中，所述第一PC5链路为所述中继与所述第一终端设备之间的PC5链路；所述第二PC5链路为所述中继与所述第二终端设备之间的PC5链路。
  2. 根据权利要求1所述的方法，其特征在于，所述第一信息用于指示第一PC5链路的用户面安全保护方法和第二PC5链路的用户面安全保护方法，包括：
    所述第一信息用于指示：所述第一PC5链路的用户面完整性保护和所述第二PC5链路的用户面完整性保护均开启或均不开启，和/或，所述第一PC5链路的用户面机密性保护和所述第二PC5链路的用户面机密性保护均开启或均不开启。
  3. 根据权利要求1或2所述的方法，其特征在于，所述方法还包括：
    接收来自中继的关于所述第一终端设备的第二请求消息，所述第二请求消息包括所述第一终端设备的PC5控制面安全策略所述中继的PC5控制面安全策略；
    根据所述第二终端设备的PC5控制面安全策略、所述第一终端设备的PC5控制面安全策略和所述中继的PC5控制面安全策略，确定第二PC5链路的控制面安全算法；
    所述第二终端设备向所述中继发送所述第二PC5链路的控制面安全算法，所述控制面安全算法用于指示所述第二PC5链路的控制面安全保护方法和所述第一PC5链路的控制面安全保护方法，其中，所述第一PC5链路的控制面安全保护方法和第二PC5链路上激活的控制面安全保护方法相同。
  4. 根据权利要求3所述的方法，其特征在于，所述第二请求消息中还包括安全终结点策略的指示，所述安全终结点策略的指示用于指示安全终结点位于所述中继上。
  5. 根据权利要求3所述的方法，其特征在于，所述控制面安全算法用于指示所述第二PC5链路的控制面安全保护方法和所述第一PC5链路的控制面安全保护方法，包括
    所述控制面安全算法用于指示：所述第一PC5链路的控制面完整性保护和所述第二PC5链路的控制面完整性保护均开启或均不开启，和/或，所述第一PC5链路的控制面机密性保护和所述第二PC5链路的控制面机密性保护均开启或均不开启。
  6. 根据权利要求3至5任一项所述的方法，其特征在于，包括：
    根据所述第二终端设备的PC5用户面安全策略、所述第一终端设备的PC5用户面安全策略和所述中继的PC5用户面安全策略，确定第一信息，包括：
    根据所述第二终端设备的PC5用户面安全策略、所述第一终端设备的PC5用户面安全策略和所述中继的PC5用户面安全策略，以及所述第二PC5链路的控制面安全算法，确定所述第一信息；
    其中，所述第二PC5链路的用户面安全保护方法的安全等级不高于所述第二PC5链路 的控制面安全保护方法的安全等级，所述第一PC5链路的用户面安全保护方法的安全等级不高于所述第一PC5链路的控制面安全保护方法的安全等级。
  7. 根据权利要求6所述的方法，其特征在于，所述第二PC5链路的用户面安全保护方法不高于所述第二PC5链路的控制面安全保护方法，所述第一PC5链路的用户面安全保护方法的安全等级不高于所述第一PC5链路的控制面安全保护方法，包括：
    当第三PC5链路的控制面机密性保护开启，则所述第三PC5链路的用户面机密性保护开启或不开启；
    当所述第三PC5链路的控制面机密性保护不开启，则所述第三PC5链路的用户面机密性保护不开启；
    当所述第三PC5链路的控制面完整性保护开启，则所述第三PC5链路的用户面完整性保护开启或不开启；
    当所述第三PC5链路的控制面完整性保护不开启，则所述第三PC5链路的用户面完整性保护不开启；
    其中，所述第三PC5链路为所述第二PC5链路或者所述第一PC5链路。
  8. 一种通信装置，其特征在于，包括：
    收发单元，用于接收来自中继的关于第一终端设备的第一请求消息；所述第一请求消息包括所述第一终端设备的PC5用户面安全策略和所述中继的PC5用户面安全策略；
    处理单元，用于根据第二终端设备的PC5用户面安全策略、所述第一终端设备的PC5用户面安全策略、所述中继的PC5用户面安全策略，确定第一信息；
    所述收发单元，还用于向所述中继发送所述第一信息，所述第一信息用于指示第一PC5链路的用户面安全保护方法和第二PC5链路的用户面安全保护方法；其中，所述第一PC5链路的用户面安全保护方法和第二PC5链路的用户面安全保护方法相同；
    其中，所述第一PC5链路为所述中继与所述第一终端设备之间的PC5链路；所述第二PC5链路为所述中继与所述第二终端设备之间的PC5链路。
  9. 根据权利要求8所述的装置，其特征在于，所述第一信息用于指示第一PC5链路的用户面安全保护方法和第二PC5链路的用户面安全保护方法，包括：
    所述第一信息用于指示：所述第一PC5链路的用户面完整性保护和所述第二PC5链路的用户面完整性保护均开启或均不开启，和/或，所述第一PC5链路的用户面机密性保护和所述第二PC5链路的用户面机密性保护均开启或均不开启。
  10. 根据权利要求8或9所述的装置，其特征在于，
    所述收发单元，还用于接收来自中继的关于所述第一终端设备的第二请求消息，所述第二请求消息包括所述第一终端设备的PC5控制面安全策略所述中继的PC5控制面安全策略；
    所述处理单元，还用于根据所述第二终端设备的PC5控制面安全策略、所述第一终端设备的PC5控制面安全策略和所述中继的PC5控制面安全策略，确定第二PC5链路的控制面安全算法；
    所述收发单元，还用于向所述中继发送所述第二PC5链路的控制面安全算法，所述控制面安全算法用于指示所述第二PC5链路的控制面安全保护方法和所述第一PC5链路的控制面安全保护方法，其中，所述第一PC5链路的控制面安全保护方法和第二PC5链路上激 活的控制面安全保护方法相同。
  11. 根据权利要求10所述的装置，其特征在于，所述第二请求消息中还包括安全终结点策略的指示，所述安全终结点策略的指示用于指示安全终结点位于所述中继上。
  12. 根据权利要求10所述的装置，其特征在于，所述控制面安全算法用于指示所述第二PC5链路的控制面安全保护方法和所述第一PC5链路的控制面安全保护方法，包括所述控制面安全算法用于指示：所述第一PC5链路的控制面完整性保护和所述第二PC5链路的控制面完整性保护均开启或均不开启，和/或，所述第一PC5链路的控制面机密性保护和所述第二PC5链路的控制面机密性保护均开启或均不开启。
  13. 根据权利要求10至12任一项所述的装置，其特征在于，
    所述处理单元根据所述第二终端设备的PC5用户面安全策略、所述第一终端设备的PC5用户面安全策略和所述中继的PC5用户面安全策略，确定第一信息，具体用于：
    根据所述第二终端设备的PC5用户面安全策略、所述第一终端设备的PC5用户面安全策略和所述中继的PC5用户面安全策略，以及所述第二PC5链路的控制面安全算法，确定所述第一信息；
    其中，所述第二PC5链路的用户面安全保护方法的安全等级不高于所述第二PC5链路的控制面安全保护方法的安全等级，所述第一PC5链路的用户面安全保护方法的安全等级不高于所述第一PC5链路的控制面安全保护方法的安全等级。
  14. 根据权利要求13所述的装置，其特征在于，所述第二PC5链路的用户面安全保护方法不高于所述第二PC5链路的控制面安全保护方法，所述第一PC5链路的用户面安全保护方法的安全等级不高于所述第一PC5链路的控制面安全保护方法，包括：
    当第三PC5链路的控制面机密性保护开启，则所述第三PC5链路的用户面机密性保护开启或不开启；
    当所述第三PC5链路的控制面机密性保护不开启，则所述第三PC5链路的用户面机密性保护不开启；
    当所述第三PC5链路的控制面完整性保护开启，则所述第三PC5链路的用户面完整性保护开启或不开启；
    当所述第三PC5链路的控制面完整性保护不开启，则所述第三PC5链路的用户面完整性保护不开启；
    其中，所述第三PC5链路为所述第二PC5链路或者所述第一PC5链路。
  15. 一种通信装置，其特征在于，所述通信装置用于执行如权利要求1至7中任一项所述的方法。
  16. 一种通信装置，其特征在于，包括：处理器，所述处理器与存储器耦合，所述存储器用于存储程序或指令，当所述程序或指令被所述处理器执行时，使得所述通信装置执行如权利要求1至7中任一项所述的方法。
  17. 一种芯片系统，其特征在于，包括：处理单元和与所述处理单元耦合的通信单元，所述处理单元用于运行计算机程序或指令，以使得处理单元执行如权利要求1至7中任意一项所述的方法。
  18. 一种计算机可读存储介质，其特征在于，所述存储介质中存储有计算机程序或指令，当所述计算机程序或指令被通信装置执行时，实现如权利要求1至7中任一项所述的方法。
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