WO2015046975A1

WO2015046975A1 - Method for securing discovery information and device therefor

Info

Publication number: WO2015046975A1
Application number: PCT/KR2014/009060
Authority: WO
Inventors: 에기윌아닐; 라자듀라이라자벨사미; 장영빈
Original assignee: 삼성전자 주식회사
Priority date: 2013-09-27
Filing date: 2014-09-26
Publication date: 2015-04-02

Abstract

The present invention relates to a method and a system for securing discovery information being transmitted through a direct radio signal in a wireless communication system which supports a device-to-device service, and a device-to-device communication method of a transmission terminal, according to one embodiment of the present invention, can comprise the steps of: synchronizing with a discovery resource cycle number; determining discovery channel logical timing information of a discovery physical channel through which discovery information is to be transmitted; generating security information by using a security key, the determined discovery channel logical timing information and the discovery information to be transmitted; and transmitting the discovery information including the security information through the discovery physical channel. According to one embodiment of the present invention, it is possible to prevent discovery information of a terminal to be wrongly transmitted due to a case where another rogue terminal receives and changes the discovery information of the terminal, or the like.

Description

Method and apparatus for securing discovery information

The present invention relates to a method and system for securing discovery information transmitted through a direct radio signal in a wireless communication system supporting a device to device service. In particular, the present invention relates to a method of replay protection and integrity protection of discovery information.

In a wireless communication system that supports device to device discovery, discovery information is transmitted by a UE that wishes to be discovered. Discovery information is sent by the UE in a discovery physical channel. The discovery information consists of an application user ID and other information of interest to the receiving UE. The discovering UE determines whether another UE is interested in it based on the received discovery information. If the proximity of a UE needs to be known by one or more authorized applications at the discovering UE, the UE is interested in discovering ProSe-enabled UEs. ProSe Discovery may be, for example, a standalone service enabler that may use information from the discovered UE for specific applications at the UE. At this time, certain applications may be allowed to use this information, for example "find a taxi nearby", "find me police officer X". Additionally, ProSe Discovery obtained in accordance with this information can be used in subsequent operations, for example, to initiate direct communication.

In current systems, discovery information sent by a UE may be received by any other UE authorized to monitor the discovery physical channel. Discovery information is sent by the UE that is authorized for transmission. However, at this time, the discovery information is transmitted in the broadcast channel, and the discovery resource is not dedicated to a specific UE for transmission. In some cases, discovery resources may be dedicated to a particular UE for transmission, but the receiving UE is not aware of the particular discovery resource used by the transmitter. Discovery information sent by a UE may be received and processed by any UE (in case of open discovery) or a specific group of UE (in case of limited discovery).

In this type of many-to-many communication on a discovery physical channel, discovery information may not be transmitted securely. The rogue UE may receive a discovery protocol data unit (PDU) transmitted on the discovery physical channel. The malicious UE may store the discovery PDU and send it later on the discovery physical channel. This can lead to receiving incorrect information for UEs receiving discovery PDUs sent by malicious UEs. For example, a Pizza Shop UE may announce an order at a specific time. Malicious UEs can replay these messages when there are no orders. Another example is that a malicious UE may play a discovery signal of a user's friend. This may cause the user's friend to be near, although the user's friend is not really close. Thus, a mechanism for replay protection must be provided to secure discovery information.

Discovery The discovery capability of a physical channel is small in size. Thus, the regeneration protection mechanism should minimize the overhead. The current playback protection mechanism uses a counter or packet number. At this time, the counter or the packet count cannot be maintained when the transmission can be received by any UE. UEs receiving the transmission may also change over time. In this case, it may not have a counter or packet number synchronized between the transmitter and the receiver. Some regenerative protection mechanisms suggest using system time (such as time in terms of hours, minutes, seconds, and minutes). However, it is not always possible to have synchronized system time through the transmitter and receiver. In addition, the system time approach may also add additional overhead when the applied system time is conveyed in the discovery information. Most of the system is time-synchronized using its mechanism, such as dividing time in terms of frames. For example, in some systems, the frame duration is 10 ms and the transmitter and receiver are synchronized with the frame boundary. Frames are numbered and roll over very quickly. For example, the 10 bit frame number rolls over every 10 seconds. Using the frame count for playback protection is not efficient because it requires a security key that will be updated every 10 seconds. Some methods use frame rate and rollover counters to reduce the frequency of security key updates. The rollover counter needs to be sent with the discovery information so that the transmitter and receiver are synchronized. But this adds overhead. Moreover, discovery information is transmitted by several UEs and received by several UEs. It may not have a rollover counter synchronized across the UEs.

Thus, there is a need for a method of securing the discovery information.

The terminal-to-device communication method according to an embodiment of the present invention is intended to prevent the terminal discovery information from being erroneously transmitted by another rogue terminal being received and changed by the other rogue terminal.

The technical problems to be achieved in the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned above will be clearly understood by those skilled in the art from the following description. Could be.

In order to achieve the above object, a communication method between terminals of a transmitting terminal according to an embodiment of the present invention includes: synchronizing with a discovery resource cycle number; Determining discovery channel logical timing information of a discovery physical channel to which discovery information is to be transmitted; Generating security information using a security key, the determined discovery channel logical timing information, and discovery information to be transmitted; And transmitting the discovery information including the security information to the discovery physical channel.

In addition, the discovery channel logical timing information may include at least one of a discovery resource cycle number, a discovery subframe number, and a discovery physical channel index.

In addition, the security information may include at least one of a message authentication code (MAC) or a digital signature (DS).

In addition, the security information may include a Cyclic Redundancy Check (CRC).

The synchronizing may include receiving a discovery resource cycle number associated with a discovery resource cycle from a base station; And synchronizing with the received discovery resource cycle number.

The generating of the security information may include: determining an absolute system time for transmitting the discovery information; And generating security information by using a security key, the determined discovery channel logical timing information, the absolute system time, and discovery information to be transmitted.

In addition, in order to achieve the above object, a communication method between terminals of a receiving terminal according to an embodiment of the present invention includes: synchronizing with a discovery resource cycle number; Receiving discovery information including first security information in a discovery physical channel; Determining discovery channel logical timing information of the discovery physical channel from which the discovery information is received; Generating second security information by using a security key, the determined discovery channel logical timing information, and the received discovery information; And verifying the first security information and the second security information.

The generating of the second security information may include determining an absolute system time at which the discovery information is received; And generating security information by using a security key, the determined discovery channel logical timing information, the absolute system time, and discovery information to be transmitted.

In addition, the terminal to the communication method of the terminal according to an embodiment of the present invention to achieve the above object, to determine the system time and system frame of the system frame / discovery slot corresponding to the discovery physical channel to which the discovery information is to be transmitted process; Generating security information using a security key, the determined system time and the discovery information to be transmitted; And transmitting the discovery information including the security information to the discovery physical channel.

The method may further include synchronizing with a coordinated universal time corresponding to the system frame.

In addition, in order to achieve the above object, a method of communication between terminals of a receiving terminal according to an embodiment of the present invention includes: receiving discovery information including first security information in a discovery physical channel; Determining a system time and a system frame of a system frame / discovery slot corresponding to the discovery physical channel through which discovery information is transmitted; Generating second security information using a security key, the determined system time and the transmitted discovery information; And verifying the first security information and the second security information.

In addition, to achieve the above object in accordance with an embodiment of the present invention, a transmitting terminal supporting communication between the terminal, the communication unit for communicating with other terminals and the base station; And synchronizing with a discovery resource cycle number, determining discovery channel logical timing information of a discovery physical channel to which discovery information is to be transmitted, generating security information using a security key, the determined discovery channel logical timing information, and discovery information to be transmitted; And a controller configured to control transmission of the discovery information including the security information to the discovery physical channel.

In addition, in order to achieve the above object, a receiving terminal supporting communication between terminals according to an embodiment of the present invention, a communication unit for communicating with other terminals and the base station; And synchronize discovery resource cycle numbers, receive discovery information including first security information on a discovery physical channel, determine discovery channel logical timing information of the discovery physical channel on which the discovery information was received, and determine a security key, the determined key. And a controller configured to generate second security information by using discovery channel logical timing information and the received discovery information and to verify the first security information and the second security information.

In addition, to achieve the above object in accordance with an embodiment of the present invention, a transmitting terminal supporting communication between the terminal, the communication unit for communicating with other terminals and the base station; And determine a system time and a system frame of a system frame corresponding to a discovery physical channel to which discovery information is to be transmitted, generate security information using a security key, the determined system time, and the discovery information to be transmitted, and generate the security information. And a controller configured to control the discovery information to be transmitted through the discovery physical channel.

In addition, in order to achieve the above object, a receiving terminal supporting communication between terminals according to an embodiment of the present invention, a communication unit for communicating with other terminals and the base station; And receiving discovery information including first security information in a discovery physical channel, determining a system time and a system frame of a system frame corresponding to the discovery physical channel on which the discovery information was transmitted, and determining a security key, the determined system time and the And a controller configured to generate second security information by using the transmitted discovery information and to control the first security information and the second security information to be verified.

In order to achieve the above object, the terminal-to-device communication method according to an embodiment of the present invention may prevent the terminal discovery information from being incorrectly transmitted by another rogue terminal received and changed by the other rogue terminal. Can be.

The effects obtainable in the present invention are not limited to the above-mentioned effects, and other effects not mentioned above may be clearly understood by those skilled in the art from the following description. will be.

1 is a diagram related to discovery resource allocation in the prior art.

2 is a diagram illustrating the numbering of discovery resource cycles according to an embodiment of the present invention.

3 illustrates discovery subframes and physical channel numbering according to an embodiment of the present invention.

4 is a diagram illustrating numbering of discovery subframes according to an embodiment of the present invention.

5 is a flowchart illustrating a discovery resource cycle numbering and synchronization method according to an embodiment of the present invention.

6 is a flowchart illustrating a method of securing discovery information in a transmitter according to an embodiment of the present invention.

7 is a diagram illustrating a method of generating a MAC or DS according to an embodiment of the present invention.

8 is a flowchart illustrating a method of verifying discovery information received at a receiver according to an embodiment of the present invention.

9 is a flowchart illustrating a method of securing discovery information in a transmitter according to another embodiment of the present invention.

10 illustrates a method of generating MAC or DS according to another embodiment of the present invention.

11 is a flowchart illustrating a method of verifying discovery information received at a receiver according to another embodiment of the present invention.

12 is a flowchart of a method of securing discovery information in a transmitter according to another embodiment of the present invention.

13 is a diagram illustrating a method of generating a MAC or DS according to another embodiment of the present invention.

14 is a flowchart illustrating a method of verifying discovery information received at a receiver according to another embodiment of the present invention.

15 is a flowchart illustrating a method of securing discovery information in a transmitter according to another embodiment of the present invention.

16 illustrates a method of generating MAC or DS according to another embodiment of the present invention.

17 is a flowchart illustrating a method of verifying discovery information received at a receiver according to another embodiment of the present invention.

18 illustrates a method of generating MAC or DS according to another embodiment of the present invention.

19 is a flowchart illustrating a method of securing discovery information in a transmitter according to an embodiment of the present invention.

20 illustrates a method of generating MAC or DS according to an embodiment of the present invention.

21 is a flowchart illustrating a method of verifying discovery information received at a receiver according to an embodiment of the present invention.

22 is a flowchart illustrating a method of securing discovery information in a transmitter according to an embodiment of the present invention.

23 is a diagram illustrating a CRC generation method according to an embodiment of the present invention.

24 is a flowchart illustrating a method of verifying discovery information received at a receiver according to an embodiment of the present invention.

25 is a diagram illustrating a CRC generation method according to another embodiment of the present invention.

26 is a diagram illustrating a CRC generation method according to another embodiment.

27 is a flowchart illustrating a method of securing discovery information in a transmitter according to an embodiment of the present invention.

28 illustrates a method of generating MAC or DS according to an embodiment of the present invention.

29 is a flowchart illustrating a method of verifying discovery information received at a receiver according to an embodiment of the present invention.

30 illustrates a method of generating MAC or DS according to another embodiment of the present invention.

31 illustrates a method of generating MAC or DS according to another embodiment of the present invention.

32 is a diagram illustrating a security key generation method according to one embodiment of the present invention.

33 is a flowchart illustrating a security key update method according to an embodiment of the present invention.

34 is a flowchart illustrating a security key exchange method according to an embodiment of the present invention.

35 is a flowchart illustrating a security key exchange method according to another embodiment of the present invention.

36 is a flowchart illustrating a security key exchange method according to another embodiment of the present invention.

37 is a flowchart illustrating a security key reception method by a UE for receiving discovery information according to an embodiment of the present invention.

38 is a flowchart illustrating a method of securing discovery information in a transmitter according to an embodiment of the present invention.

39 is a diagram illustrating an encryption method according to an embodiment of the present invention.

40 is a flowchart illustrating a method of verifying discovery information received at a receiver according to an embodiment of the present invention.

41 is a diagram illustrating an example of a block diagram of a terminal according to an embodiment of the present invention.

42 is a diagram illustrating an example of a block diagram of a base station according to an embodiment of the present invention.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

In describing the embodiments, descriptions of technical contents that are well known in the technical field to which the embodiments of the present disclosure belong and are not directly related to the embodiments of the present specification will be omitted. This is to more clearly communicate without obscure the subject matter of the embodiments of the present disclosure by omitting unnecessary description.

In the following description of the embodiments of the present disclosure, when it is determined that detailed descriptions of related known functions or configurations may unnecessarily obscure the subject matter of the present disclosure, the detailed description thereof will be omitted. Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. Terms to be described later are terms defined in consideration of functions in the present invention, and may be changed according to intentions or customs of users or operators. Therefore, the definition should be made based on the contents throughout the specification.

Hereinafter, the present invention will be described according to various embodiments.

First, a description will be given of the generation of Message Authentication Code (MAC) / Digital Signature (DS) using Discovery Channel Logical Timing Information.

1 is a diagram related to discovery resource allocation in the prior art.

The discovery information is transmitted on a discovery physical channel in discovery subframes. 2, the allocation of discovery resources in the current system or in the prior art is shown. A base station (BS) or group leader allocates discovery subframes for every Discovery Resource Cycle (DRC). At this time, the information on the discovery subframe is transmitted to the downlink using the system information. A BS is present where discovery and discoverable user equipment (UE) are within coverage of a communication network. A group leader (a specific UE with the ability to coordinate resources, provide timing synchronization, etc.) exists when the discovery and discoverable UEs are not within coverage of the communication network. The discovery resource cycle consists of a discovery resource interval (DRI) and a non-discovery resource interval. The discovery subframe is in the discovery resource interval. Each discovery subframe consists of a discovery physical channel of fixed size. Each discovery physical channel may carry one Discovery Protocol Data Unit (PDU) of small size. The discovery physical channel is small because the large size of the physical channel reduces the coverage of the discovery physical channel (ie, the distance at which the transmitted discovery physical channel is received).

Referring to FIG. 2, according to an embodiment of the present invention, each discovery resource cycle (DRC) may be assigned a number. DRC numbers may be assigned to each discovery resource cycle sequentially. In the case of a discovery resource number of size 'n' bits, the discovery resource cycle number rolls over every 2n DRCs. A DRC number zero may be assigned to a DRC starting with frame number 'X' where X mod 2n = Y (0 or some positive integer). The BS or group leader can assign a DRC number to the DRC. The BS or the group leader may broadcast the DRC number or transmit the DRC number to the terminal as a dedicated signal in a unicast manner. In one embodiment, the DRC number may be broadcast per discovery resource cycle. In another embodiment, the DRC number may be broadcast per 't' discovery resource cycle. According to an embodiment, the DRC number may be broadcast using a system information message or a system information block or packet data common control channel.

According to an embodiment, the DRC number may be broadcast / unicast in the broadcast / unicast information corresponding to the discovery resource cycle in which the broadcast / unicaster information is received. Or, according to an embodiment, the DRC number may be broadcast / unicast in the broadcast / unicast information corresponding to the discovery resource cycle following the discovery resource cycle in which the broadcast / unicaster information is received. Alternatively, the DRC number may be broadcast / unicast in broadcast / unicast information corresponding to the 'P' th discovery resource cycle following the discovery resource cycle in which the broadcast / unicaster information is received. In this case, 'P' may be set in advance.

FIG. 3 illustrates discovery subframes and physical channel numbering according to an embodiment of the present invention, and FIG. 4 illustrates numbering of discovery subframes according to an embodiment of the present invention.

3 and 4, discovery subframes in a discovery resource interval may be numbered. In addition to FIGS. 3 and 4, those skilled in the art may use other methods of numbering. Discovery subframe numbering may be unique across discovery subframes in the discovery resource interval. Alternatively, discovery subframes may be numbered throughout the discovery resource cycle. For example, DRC 'P' may be labeled with 1 to X, and DRC 'P + 1' may be labeled with 'X + 1' to 'X + N'.

According to one embodiment, discovery subframes in the DRI may be identified by frame number and subframe number. Each frame (ie, 10 ms) can be numbered. According to an embodiment, each frame may have 10 subframes numbered from 0 to 9.

In addition, according to an embodiment, as shown in FIG. 4, the entire discovery subframe may be sequentially numbered. Alternatively, according to an embodiment, only the discovery subframe may be numbered.

According to an embodiment, the discovery physical channels may also be numbered as illustrated in FIG. 3. In one embodiment, discovery physical channel numbering may be unique across discovery physical channels within a discovery subframe. In another embodiment, discovery physical channels may be numbered across discovery subframes.

In one embodiment, the discovery resource cycle may consist of multiple DRIs. In this case, the DRIs within the discovery resource cycle may also be numbered. In some embodiments, the DRI may be the same as the DRC.

Referring to FIG. 5, discovery resource cycle numbering and synchronization may be performed by a UE participating in discovery (a transmitting UE as well as a receiving UE). In this case, the discovery subframe number, the DRI number, and the discovery physical channel index may be implicitly determined by the UE after synchronizing with the DRC number.

In detail, in step 510, the base station may number at least one of a discovery physical channel, a discovery subframe, a discovery resource interval, and a discovery resource cycle.

Thereafter, in step 520, the base station transmits a discovery resource cycle number associated with the discovery resource cycle, and in step 530, the UE receives a transmission from the base station or the centralized coordinator and synchronizes with the discovery resource cycle number from the received transmission information. .

In one embodiment of the present invention, the security key may be a symmetric key that the transmitter and receiver use equally. In another embodiment of the present invention, the security key may be an asymmetric key where the transmitter and receiver use different keys. According to an embodiment a key pair consisting of a public key and a private key is used, where the private key is used by the transmitter and the public key can be used by the receiver. In the case of a symmetric key, the security algorithm generates a Message Authentication Code (MAC), while in the case of an asymmetric key, the security algorithm generates a Digital Signature (DS).

Referring to the security key according to an embodiment of the present invention, a symmetric security key or an asymmetric security key pair may be common to open discovery for all types of services. In another embodiment of the present invention, a symmetric security key or asymmetric security key pair may be specific to a particular service type. For example, the UE may support one or more services, each identified by a D2D application ID or a D2D service ID. When the UE requests the D2D application code or the D2D service code corresponding to the D2D application ID or the D2D service ID, the UE may obtain a security key from the D2D server. The D2D service code or D2D application code may be sent by the UE as part of the discovery information. Therefore, each UE may have a plurality of security keys, one for each D2D application ID / D2D service ID or D2D application code / D2D service code. In another embodiment, the symmetric security key or asymmetric security key pair may also be specific to the UE sending discovery information. In another embodiment, the symmetric security key or asymmetric security key pair may also be specific to a UE sending discovery information to a group of UEs.

The security key used by the transmitter and receiver is updated by the UEs participating in discovery whenever the DRC number rolls over in this approach.

6 is a flowchart illustrating a method of securing discovery information in a transmitter according to an embodiment of the present invention, and FIG. 7 is a diagram illustrating a method of generating a MAC or DS according to an embodiment of the present invention.

Referring to FIG. 6, a transmitter (ie, a D2D UE) has discovery information that needs to be safely transmitted in a discovery channel. First, in step 610, the transmitter synchronizes with DRC numbering if it is not already synchronized. The transmitter receives broadcast information carrying the DRC number and synchronizes with the DRC cycle. In this case, the broadcast information may be transmitted by the BS or the group leader. Before sending any discovery information, the transmitter must be synchronized with DRC numbering and DRC. Since the method of synchronizing with the DRC numbering is illustrated in the above-mentioned part of FIG. 5, a detailed description thereof will be omitted.

In an embodiment of the present invention, the transmitter determines information about a logical time at which a discovery physical channel carrying discovery information is transmitted in step 620. The determined timing information may include at least one of a DRC number, a discovery subframe number, and a discovery physical channel index of the discovery physical channel. According to an embodiment, if one DRC has multiple DRIs and the DRI is numbered, the DRI number may also be determined. According to an embodiment, instead of the discovery subframe number, <frame number and subframe number> may be used, wherein the subframes in the frame may be numbered.

Thereafter, the transmitter may generate a message authentication code (MAC) or digital signature (DS) using the security key, the determined discovery channel logical timing information, and the transmitted discovery information in operation 630.

Specifically, according to an embodiment of the present invention, in addition to the discovery information and security key to be secured, the discovery physical channel index, DRC number, and discovery subframe number (or frame number and Subframe number) may be provided to a security algorithm as illustrated in FIG. If the security key is specific to the discovery information to be sent, the transmitter can use the appropriate security key. In one embodiment where one DRC has multiple DRIs and the DRI is numbered, the DRI number may also be used as an additional input to the security algorithm.

The security algorithm then generates a message authentication code (MAC) or digital signature (DS). The generated MAC or DS may then be added to the discovery information. In this case, in some systems, the MAC may be referred to as a message integrity code (MIC).

Then, in operation 640, discovery information secured using the MAC or the DS may be transmitted in the discovery channel.

According to an embodiment, the secured discovery information may be fragmented and transmitted over multiple discovery physical channels. In this case, the discovery physical channel index, discovery subframe number (or frame number and subframe number), and DRC number of one of the fragments (first fragment or last fragment) may be used to secure the discovery information. Alternatively, the discovery physical channel index, discovery subframe number (or frame number and subframe number), and DRC number of one of all fragments may be used. In some embodiments, instead of securing unfragmented discovery information, the discovery information may be secured after being fragmented. In this case, the discovery physical channel index, discovery subframe number (or frame number and subframe number), and DRC number of each fragment may be used to secure discovery information.

Referring to FIG. 7, in an embodiment of the present invention, a discovery PDU carrying secure discovery information may include discovery information and a MAC or DS. In addition, the discovery PDU may include a security indicator (security_indicator) indicating whether security is applied. According to an embodiment, the security indicator may not be necessary if security is always applied. According to an embodiment, the security indicator may not be needed if security is based on the discovery type or category and the discovery type or category is indicated using one of the fields in the header of the discovery PDU. The discovery PDU carrying the secure discovery information may also include a security key index to identify the security key used to secure the discovery information.

Referring to FIG. 8, in step 810, the receiver synchronizes with DRC numbering when it is not already synchronized. The receiver receives broadcast information carrying the DRC number and synchronizes with the DRC cycle. In this case, the broadcast information may be transmitted by the BS or the group leader. Before receiving any discovery information, the receiver must be synchronized with DRC numbering and DRC.

After synchronizing with the DRC numbering, the receiver monitors the discovery channel in step 820. The receiver (eg, D2D UE) may receive secure discovery information in the discovery channel.

Thereafter, in step 830, the receiver determines the information about the time at which the discovery physical channel carrying the discovery information is received. The determined timing information may include at least one of a DRC number, a discovery subframe number (or a frame number and a subframe number), and a discovery physical channel index of the discovery physical channel. In one embodiment where one DRC has multiple DRIs and the DRI is numbered, the DRI number may also be determined.

Thereafter, the receiver may generate a message authentication code (MAC) or digital signature (DS) using the security key, the determined discovery channel logical timing information, and the received discovery information in step 840.

Specifically, according to an embodiment of the present invention, in addition to the discovery information and security key to be secured, the discovery physical channel index, the discovery subframe number (or frame number and subframe number) of the discovery physical channel in which the discovery information to be protected is received. , And DRC numbers may be provided to the security algorithm as illustrated in FIG. The security algorithm can be executed at the receiver or at the D2D server. The receiver may transmit the received information (MAC or DS, DRC number, discovery subframe number, and discovery physical channel index) and discovery information to the D2D server. In one embodiment where one DRC has multiple DRIs and the DRI is numbered, the DRI number may also be used as an additional input to the security algorithm. The security algorithm then generates a MAC or DS.

In operation 850, the receiver may compare the generated MAC or DS with the MAC or DS received together with the discovery information from the transmitter. When a rogue sender replays a message, the DRC number, discovery subframe number (or frame number and subframe number) that the receiver receives, and the discovery physical channel index of the discovery physical channel stop transmitting at the genuine transmitter. Will differ from the one used for the purpose. This will result in failure of MAC or DS verification at the receiver.

9 is a flowchart illustrating a method of securing discovery information in a transmitter according to another embodiment of the present invention, and FIG. 10 is a diagram illustrating a method of generating a MAC or DS according to another embodiment of the present invention. 11 is a flowchart of a method of verifying discovery information received at a receiver according to another embodiment of the present invention.

This <Example 1B> is a reproduction protection method illustrated in the part related to FIGS. 6, 7 and 8 except that the transmitter and the receiver do not use the discovery physical channel index of the discovery physical channel for transmitting and receiving discovery information, respectively. It is the same as <Example 1A>.

When the discovery physical channel is frequency division multiplexing in a subframe, when the discovery PDU transmitted by the UE in the subframe cannot be reproduced by the malicious UE in the same subframe, the discovery physical channel index may not be used. On the other hand, in the case of time division multiplexing of discovery physical channels in one subframe, a replay attack is possible by a malicious UE, and in this case, a reproduction protection method as described in the above-described <Example 1A> should be used. do. However, if the subframe duration is very small in case of time division multiplexing of the discovery physical channel in one subframe, the method of the present embodiment 1B may be used.

Hereinafter, the <Example 1B> will be briefly described. For convenience of description, descriptions of parts common to <Example 1A> will be omitted.

Referring to FIG. 9, the transmitter has discovery information that needs to be safely transmitted in the discovery channel. At this time, in step 910, the transmitter synchronizes with DRC numbering if it is not already synchronized. Since a detailed description thereof has been described in a part related to FIG. 6, it will be omitted.

Thereafter, in step 920, the transmitter determines information about a logical time at which a discovery physical channel carrying discovery information is transmitted. In this case, the determined timing information may include a DRC number and a discovery subframe number (or frame number and subframe number). However, unlike <Example 1A> described above with reference to FIG. 6, the discovery physical channel index of the discovery physical channel is not included.

In operation 930, the transmitter may generate a MAC or DS using the security key, the determined discovery channel logical timing information, and the discovery information to be transmitted. In this case, in addition to the discovery information and the security key to be secured, the DRC number and the discovery subframe number (or frame number and subframe number) to which the discovery information to be secured is transmitted are stored in a security algorithm as illustrated in FIG. 10. Can be provided. As shown in FIG. 10, unlike FIG. 7, the index of the discovery physical channel is not provided to the security algorithm. The security algorithm then generates a message authentication code (MAC) or digital signature (DS). The generated MAC or DS may then be added to the discovery information.

Then, in operation 940, discovery information secured using the MAC or the DS may be transmitted in the discovery channel.

Referring to FIG. 11, in step 1110, the receiver synchronizes with DRC numbering when it is not already synchronized. The receiver receives broadcast information carrying the DRC number and synchronizes with the DRC cycle. In this case, broadcast information may be transmitted by the BS or the group leader. Before receiving any discovery information, the receiver must be synchronized with DRC numbering and DRC.

After synchronizing with the DRC numbering, the receiver monitors the discovery channel in step 1120. The receiver may receive secure discovery information in the discovery channel.

Thereafter, in step 1130, the receiver determines information about a time at which a discovery physical channel carrying discovery information is received. The determined timing information may include at least one of a DRC number, a discovery subframe number (or a frame number and a subframe number). However, unlike <Example 1A> described above with reference to FIG. 8, the discovery physical channel index of the discovery physical channel is not included.

Thereafter, in step 1140, the receiver may generate a MAC or DS using the security key, the determined discovery channel logical timing information, and the received discovery information. In this case, in addition to the discovery information and security key to be protected, the discovery subframe number (or frame number and subframe number) and the DRC number where the discovery information to be secured is received may be provided to the security algorithm as illustrated in FIG. 10. . As shown in FIG. 10, unlike FIG. 7, the index of the discovery physical channel is not provided to the security algorithm. The security algorithm then generates a MAC or DS.

In operation 1150, the receiver may compare the generated MAC or DS with the MAC or DS received together with the discovery information from the transmitter.

12 is a flowchart illustrating a method for securing discovery information in a transmitter according to another embodiment of the present invention, and FIG. 13 is a diagram illustrating a method of generating a MAC or DS according to another embodiment of the present invention. 14 is a flowchart illustrating a method of verifying discovery information received at a receiver according to another embodiment of the present invention.

This <embodiment 1C> is a reproduction protection method illustrated in the part related to FIGS. 9, 10, and 11 except that a transmitter and a receiver do not use a discovery subframe number of a discovery physical channel that transmits and receives discovery information, respectively. It is the same as <Example 1B>.

The discovery subframe number is not needed when it is assumed that the discovery information sent by the UE is not updated during the discovery resource interval. In this case, even if the malicious UE plays the discovery PDU during the DRI, it does not affect the receiving UE. This is mainly true for open discovery (eg, advertisements, etc.). In limited discovery, it is always a good idea to use the discovery subframe number. However, if the DRI is small, the malicious UE may not be able to play within the DRI even for limited discovery, and the discovery subframe number may not be needed. Thus, this <Embodiment 1C> can be used when the discovery resource interval is small.

Hereinafter, the <Example 1C> will be briefly described. For convenience of description, descriptions of parts common to <Example 1A> and <Example 1B> will be omitted.

Referring to FIG. 12, a transmitter has discovery information that needs to be safely transmitted in a discovery channel. At this time, in step 1210, the transmitter synchronizes with DRC numbering if it is not already synchronized. Since a detailed description thereof has been described in a part related to FIG. 6, it will be omitted.

Thereafter, in step 1220, the transmitter determines information about a logical time at which a discovery physical channel carrying discovery information is transmitted. In this case, the determined timing information may include a DRC number. However, unlike <Example 1B> described above with reference to FIG. 9, the discovery subframe number is not included.

In operation 1230, the transmitter may generate a MAC or DS using the security key, the determined discovery channel logical timing information, and the discovery information to be transmitted. In this case, in addition to the discovery information to be secured and the security key, the DRC number to which the discovery information to be secured is transmitted may be provided to a security algorithm as illustrated in FIG. 13. As shown in FIG. 13, unlike FIG. 10, the discovery subframe number is not provided to the security algorithm. The security algorithm then generates a message authentication code (MAC) or digital signature (DS). The generated MAC or DS may then be added to the discovery information.

Then, in operation 1240, discovery information secured using the MAC or the DS may be transmitted in the discovery channel.

Referring to FIG. 14, the receiver synchronizes with DRC numbering if it is not already synchronized in step 1410. The receiver receives broadcast information carrying the DRC number and synchronizes with the DRC cycle. In this case, broadcast information may be transmitted by the BS or the group leader. Before receiving any discovery information, the receiver must be synchronized with DRC numbering and DRC.

After synchronizing with the DRC numbering, the receiver monitors the discovery channel in step 1420. The receiver may receive secure discovery information in the discovery channel.

Thereafter, in step 1430, the receiver determines information about the time at which the discovery physical channel carrying the discovery information is received. The determined timing information may include a DRC number. However, unlike <Example 1B> described above with reference to FIG. 11, the discovery subframe number of the discovery physical channel is not included.

Thereafter, the receiver may generate a MAC or DS using the security key, the determined discovery channel logical timing information, and the received discovery information in step 1440. In this case, in addition to the discovery information to be protected and the security key, the DRC number for receiving the discovery information to be secured may be provided to the security algorithm as illustrated in FIG. 13. As shown in FIG. 13, unlike FIG. 10, the discovery subframe number is not provided to the security algorithm. The security algorithm then generates a MAC or DS.

In operation 1450, the receiver may compare the generated MAC or DS with the MAC or DS received together with the discovery information from the transmitter.

FIG. 15 is a flowchart illustrating a method for securing discovery information in a transmitter according to another embodiment of the present invention, and FIG. 16 illustrates a method of generating a MAC or DS according to another embodiment of the present invention. 17 is a flowchart illustrating a method of verifying discovery information received at a receiver according to another embodiment of the present invention.

12D and 13 except that the last DRC number of the discovery physical channel through which discovery information to be protected is last transmitted instead of the DRC number of the discovery physical channel through which discovery information is transmitted is provided to the security algorithm. And the reproducing protection method illustrated in the section related to FIG. 14.

This method assumes that the same discovery information is transmitted to multiple DRCs. For such multiple DRCs, the discovery information is secured once, and the secured discovery information is sent for multiple DRCs. As a result, the transmitter does not need to generate secure discovery information per transmission. This can reduce the transmission process.

Referring to FIG. 16, not only the MAC or DS but also the last DRC number may be added to the discovery PDU.

In some embodiments, if the discovery PDU is sent with the same discovery physical channel index and / or discovery subframe number in all DRC cycles until the last DRC cycle indicated by the last DRC number, the discovery physical channel index and / or discovery subframe number is Can be used with the last DRC number.

If the DRC number of the PDU is equal to or greater than the DRC number of the discovery physical channel receiving the discovery information, the receiving UE processes the received PDU. The receiving UE uses the DRC number of the PDU along with the security key to generate the MAC. The generated MAC is then compared with the received MAC. If the malicious UE plays the message, the DRC number of the discovery physical channel that the UE receives will be different from the number used for transmission. This will result in failure of MAC verification. <Timing Information and Security Key of Discovery Physical Channel Represented by DRC Number> The tuple is unique to transmission of discovery information.

Hereinafter, the <Example 1D> will be briefly described. For convenience of description, descriptions of parts common to <Example 1A> to <Example 1C> will be omitted.

Referring to FIG. 15, the transmitter has discovery information that needs to be safely transmitted in the discovery channel. At this time, in step 1510, the transmitter synchronizes with DRC numbering if it is not already synchronized. Since a detailed description thereof has been described in a part related to FIG. 6, it will be omitted.

Thereafter, in step 1520, the transmitter determines information about a logical time at which a discovery physical channel carrying discovery information is transmitted. In this case, the determined timing information may include a DRC number.

In operation 1530, the transmitter may generate a MAC or DS using the security key, the determined discovery channel logical timing information, and the discovery information to be transmitted. In this case, in addition to the discovery information and security key to be secured, the last DRC number may be provided to a security algorithm as illustrated in FIG. 16. The security algorithm then generates a message authentication code (MAC) or digital signature (DS). The generated MAC or DS may then be added to the discovery information.

Then, in operation 1540, discovery information secured using the MAC or the DS may be transmitted in the discovery channel.

Referring to FIG. 17, the receiver performs synchronization with DRC numbering when it is not already synchronized in step 1710. The receiver receives broadcast information carrying the DRC number and synchronizes with the DRC cycle. In this case, broadcast information may be transmitted by the BS or the group leader. Before receiving any discovery information, the receiver must be synchronized with DRC numbering and DRC.

After synchronizing with the DRC numbering, the receiver monitors the discovery channel in step 1720. The receiver may receive secure discovery information in the discovery channel.

Thereafter, in step 1730, the receiver determines information about a time at which a discovery physical channel carrying discovery information is received. The determined timing information may include a discovery resource cycle number.

Then, if the DRC number of the PDU is greater than or equal to the DRC number where the discovery information is received, the receiver may generate a MAC or DS using the security key, the determined discovery channel logical timing information and the received discovery information in step 1740. Can be. At this time, in addition to the discovery information and security key to be protected, the last DRC number may be provided to the security algorithm as illustrated in FIG. 16. The security algorithm then generates a MAC or DS.

In operation 1750, the receiver may compare the generated MAC or DS with the MAC or DS received together with the discovery information from the transmitter.

This <Embodiment 1E> is illustrated in the parts related to FIGS. 15, 16, and 17 except that a difference between the last DRC number of the DRC to which discovery information is transmitted and the current DRC number is included in the discovery PDU instead of the last DRC number. It is the same as that of <Example 1D>, which is a reproduced protection method.

This reduces the overhead. However, this requires an update of the DRC Number field of the Discovery PDU per transmission. Since the transmitter and receiver methods are the same as those of FIGS. 15 and 17, detailed descriptions thereof will be omitted.

<Second Embodiment: Message Authentication Code (MAC) / Digital Signature (DS) Generation Using Discovery Channel Logical Timing Information and Partial Absolute System Time Information

In the second embodiment, synchronization of discovery resource and discovery resource cycle numbering, discovery subframe numbering, discovery physical channel numbering and discovery resource cycle numbering are the same as illustrated in the first embodiment.

In one embodiment of the invention, the security key may be a symmetric key that the transmitter and receiver use equally. In another embodiment of the present invention, the security key may be an asymmetric key where the transmitter and receiver use different keys. According to an embodiment a key pair consisting of a public key and a private key is used, where the private key is used by the transmitter and the public key can be used by the receiver. In the case of symmetric keys, the security algorithm generates a MAC, while in the case of asymmetric keys, the security algorithm generates a DS.

In one embodiment of the present invention, symmetric security keys or asymmetric security key pairs may be common to open discovery for all types of services. In another embodiment of the present invention, a symmetric security key or asymmetric security key pair may be specific to a particular service type. For example, the UE may support one or more services, each identified by a D2D application ID or a D2D service ID. When the UE requests the D2D application code or the D2D service code corresponding to the D2D application ID or the D2D service ID, the UE may obtain a security key from the D2D server. The D2D service code or D2D application code may be sent by the UE as part of the discovery information. Therefore, each UE may have a plurality of security keys, one for each D2D application ID / D2D service ID or D2D application code / D2D service code. In another embodiment, the symmetric security key or asymmetric security key pair may also be specific to the UE sending discovery information. In another embodiment, the symmetric security key or asymmetric security key pair may also be specific to a UE sending discovery information to a group of UEs.

Referring to the security key update trigger according to an embodiment of the present invention, in this approach, the security key does not need to be updated when the DRC rolls over.

19 is a flowchart illustrating a method of securing discovery information in a transmitter according to an embodiment of the present invention, and FIG. 20 is a diagram illustrating a method of generating a MAC or DS according to an embodiment of the present invention.

Referring to FIG. 19, a transmitter (ie, a D2D UE) has discovery information that needs to be safely transmitted in a discovery channel. First, in step 1910, the transmitter synchronizes with DRC numbering if it is not already synchronized. The transmitter receives broadcast information carrying the DRC number and synchronizes with the DRC cycle. In this case, broadcast information may be transmitted by the BS or the group leader. Before sending any discovery information, the transmitter must be synchronized with DRC numbering and DRC. Since the method of synchronizing with the DRC numbering is illustrated in the above-mentioned part of FIG. 5, a detailed description thereof will be omitted.

In an embodiment of the present invention, the transmitter determines information about a logical time at which a discovery physical channel carrying discovery information is transmitted in step 1920. The determined timing information may include at least one of a DRC number, a discovery subframe number (or a frame number and a subframe number), and a discovery physical channel index of the discovery physical channel. According to an embodiment, in one embodiment where one DRC has multiple DRIs and the DRIs are numbered, the DRI numbers may also be determined.

Thereafter, in step 1930, the transmitter determines partial information on an absolute system time over which a discovery physical channel carrying discovery information is transmitted. Absolute system time may include year, month, date, hour, minute, and second. The determined partial absolute system time information may include the year, month and day for which this discovery information is sent.

1. According to an embodiment, the transmitter may determine this using a system clock. All UEs maintain system time, so this information can be easily determined. In another embodiment, the network may send partial information about the system along with the D2D configuration. There may be a difference between the dates of the transmitter and receiver for several hours during the date change. In this method to resolve the difference in system times of the transmitter and receiver, the transmitter cannot transmit for a fixed period of time after the date is changed. Alternatively, the transmitter can transmit without worrying about differences in system time. The receiver will not receive it if there is a difference of any date. Alternatively, the transmitter can add date information to the discovery information. This can be added for all discovery information transfers. Alternatively, it may be added to the discovery information during the time window when a date change occurs.

2. In another embodiment, the BS may send partial information about the system time with the DRC number. The BS may indicate its date corresponding to the DRC. This can resolve the time difference when the date changes.

3. Alternatively, the network may send partial information about the system along with the D2D configuration.

In some embodiments, the determined partial information for the absolute system time information may include additional information such as hour, minute, second, or week information.

The transmitter may then generate a MAC or DS using the security key, the determined discovery channel logical timing information, the determined discovery channel absolute system time and the transmitted discovery information in step 1940.

Specifically, according to an embodiment of the present invention, in addition to the discovery information to be secured and the security key, the discovery physical channel index, the discovery subframe number, and the DRC number of the discovery physical channel to which the discovery information to be secured is transmitted are transmitted, and the discovery to be protected. Partial information of absolute system time at which information is transmitted may be provided to the security algorithm as shown in FIG. 20.

The security algorithm then generates a message authentication code (MAC) or digital signature (DS). The generated MAC or DS may then be added to the discovery information.

Then, in step 1950, the transmitter may transmit discovery information secured using the MAC or the DS in the discovery channel.

In some embodiments, secure discovery information may be fragmented and transmitted over multiple discovery physical channels. In this case, the discovery physical channel index, discovery subframe number, and DRC number of one of the fragments (first fragment or last fragment) may be used to secure the discovery information. Alternatively, the discovery physical channel index, discovery subframe number, and DRC number of one of all fragments may be used. In some embodiments, instead of securing unfragmented discovery information, the discovery information may be secured after being fragmented. In this case, the discovery physical channel index, discovery subframe number, and DRC number of each fragment may be used to secure the discovery information.

Referring to FIG. 20, in an embodiment of the present invention, a discovery PDU carrying secure discovery information may include discovery information and a MAC or DS. In addition, the discovery PDU may include a security indicator (security_indicator) indicating whether security is applied. According to an embodiment, the security indicator may not be necessary if security is always applied. According to an embodiment, the security indicator may not be needed if security is based on the discovery type or category and the discovery type or category is indicated using one of the fields in the header of the discovery PDU. The discovery PDU carrying the secure discovery information may also include a security key index to identify the security key used to secure the discovery information. In addition, as illustrated in FIG. 20, the discovery PDU may further include information regarding a date in addition to the discovery information and the MAC or DS.

Referring to FIG. 21, in step 2110, the receiver synchronizes with DRC numbering when it is not already synchronized. The receiver receives broadcast information carrying the DRC number and synchronizes with the DRC cycle. In this case, the broadcast information may be transmitted by the BS or the group leader. Before receiving any discovery information, the receiver must be synchronized with DRC numbering and DRC.

After synchronizing with the DRC numbering, the receiver monitors the discovery channel in step 2120. The receiver (eg, D2D UE) may receive secure discovery information in the discovery channel.

Thereafter, in step 2130, the receiver determines information about a time at which a discovery physical channel carrying discovery information is received. The determined timing information may include at least one of a DRC number, a discovery subframe number (or a frame number and a subframe number), and a discovery physical channel index of the discovery physical channel. In one embodiment where one DRC has multiple DRIs and the DRI is numbered, the DRI number may also be determined.

In operation 2140, the receiver may determine partial information about an absolute system time at which a discovery physical channel that carries discovery information is received. The determined partial information about the absolute system time information may include information about the year, month and day when such discovery information is received.

1. In one embodiment, the receiver can determine this absolute system time information using its system clock. Since all UEs maintain system time, this information can be easily determined. In another embodiment, the network may send partial information about the system along with the D2D configuration. There may be a difference between the dates of the transmitter and receiver for several hours during the date change. In this method to resolve the difference in system times of the transmitter and the receiver, the receiver cannot receive for a fixed period of time after the date is changed. Alternatively, the receiver can receive without worrying about differences in system time. The receiver will not receive it if there is any date difference. Alternatively, the receiver can use the date information received in the discovery information instead of its date.

In some embodiments, the determined partial information for the absolute system time information may consist of additional information such as hour, minute, second or week information.

Thereafter, in step 2150, the receiver may generate a MAC or DS using the security key, the determined discovery channel logical timing information, and the received discovery information.

Specifically, according to an embodiment of the present invention, in addition to the discovery information and security key to be secured, the discovery physical channel index, the discovery subframe number (or frame number and subframe number) of the discovery physical channel in which the discovery information to be secured is received. , And DRC numbers may be provided to the security algorithm as illustrated in FIG. 20. The security algorithm can be executed at the receiver or at the D2D server. The receiver then transmits the received information (MAC or DS, DRC number, discovery subframe number (or frame number and subframe number), partial information of system time, and discovery physical channel index) and discovery information to the D2D server. Can be. In one embodiment where one DRC has multiple DRIs and the DRI is numbered, the DRI number may also be used as an additional input to the security algorithm. The security algorithm then generates a MAC or DS.

The receiver may then compare the MAC or DS generated in step 2160 with the MAC or DS received with the discovery information from the transmitter. When the rogue sender plays the message, the DRC number, discovery subframe number, and discovery physical channel index of the discovery physical channel that the receiver receives will be different than that used for transmission at the genuine transmitter. This will result in failure of MAC or DS verification at the receiver.

In an alternative embodiment to the second embodiment, the logical timing information may include the following information.

a) DRC number and discovery subframe number: If the discovery physical channel is frequency division multiplexed in a subframe, the discovery physical channel when the discovery PDU transmitted by the UE in the subframe cannot be played by the malicious UE in the same subframe. You can not use indexes. In the case of time division multiplexing of discovery physical channels in one subframe, a replay attack is possible by a malicious UE, where a replay protection method as described in <Example 1A> may be used. However, if the subframe duration is very small in case of time division multiplexing of the discovery physical channel in one subframe, this method may also be used. Since this method is similar to the above-described <Example 1B>, a detailed description thereof will be omitted.

b) DRC Number: The discovery subframe number is not needed when it is assumed that the discovery information sent by the UE is not updated during the discovery resource interval. In this case, even if the malicious UE plays the discovery PDU during the DRI, it does not affect the receiving UE. This is mainly true for open discovery (eg advertising). In limited discovery, it is always desirable to use the discovery subframe number. However, if the DRI is small, the malicious UE may not be able to play within the DRI even for limited discovery, and the discovery subframe number may not be needed. Thus, this method can be used when the discovery resource interval is small. Since this method is similar to the above-described <Example 1C>, a detailed description thereof will be omitted.

c) Last DRC Number: The last DRC number of the discovery physical channel on which discovery information to be protected is last transmitted may be provided to the security algorithm. This method assumes that the same discovery information is sent to multiple DRCs. For such multiple DRCs, the discovery information is secured once, and the secured discovery information is sent for multiple DRCs. As a result, the transmitter does not need to generate secure discovery information per transmission. This reduces the transmission process. The last DRC number may also be added to the discovery PDU in addition to the MAC. This method is similar to the above-described <Example 1D> and <Example 1E>, so a detailed description thereof will be omitted.

Synchronization of discovery resource and discovery resource cycle numbering, discovery subframe numbering, discovery physical channel numbering, and discovery resource cycle numbering in connection with the discovery channel logical timing in the third embodiment is the same as illustrated in the first embodiment. Do.

In one embodiment of the invention, the security key may be a symmetric key that the transmitter and receiver use equally. In another embodiment of the present invention, the security key may be an asymmetric key where the transmitter and receiver use different keys. According to an embodiment, a key pair consisting of a public key and a private key is used, where the private key is used by the transmitter and the public key can be used by the receiver. In the case of symmetric keys, the security algorithm generates a MAC, while in the case of asymmetric keys, the security algorithm generates a DS.

The security key used by the transmitter and receiver is updated by the UEs participating in discovery each time the DRC number rolls over.

Hereinafter, a method of generating a discovery PDU CRC will be described.

22 is a flowchart illustrating a method for securing discovery information in a transmitter according to an embodiment of the present invention, FIG. 23 is a diagram illustrating a CRC generation method according to an embodiment of the present invention, and FIG. A flowchart of a method of verifying discovery information received at a receiver according to an embodiment of the present invention.

Referring to FIG. 22, in step 2210, the transmitter synchronizes with DRC numbering when it is not already synchronized. Before sending any information, the transmitter must be synchronized with DRC numbering and DRC. Since the method of synchronizing with the DRC numbering is illustrated in the above-mentioned part of FIG. 5, a detailed description thereof will be omitted.

The transmitter may then determine information about the discovery channel logic time of the discovery channel carrying the discovery information in step 2220. The determined discovery channel logical timing information may include a DRC number. In this case, according to an embodiment, the apparatus may further include at least one of a discovery subframe number (or a frame number and a subframe number) and a discovery physical channel index.

In operation 2230, the transmitter may generate a CRC using the security key, the determined discovery channel logic timing information, and the transmitted discovery information.

Specifically, referring to FIG. 23, the CRC generator 2310 may generate a CRC 2340 using the discovery PDU bit 2330, the security key 2320, and the CRC mask 2350. In this case, the CRC mask 2350 may include a discovery physical channel transmission time, that is, a DRC number and / or a discovery subframe number (or a frame number and a subframe number) and / or a discovery physical channel index.

Thereafter, in step 2240, the transmitter may transmit the discovery information secured in the discovery channel together with the CRC.

Looking at the operation of the receiver with reference to FIG. 24, first, the receiver synchronizes with DRC numbering if it is not already synchronized in step 2410. Before receiving any discovery information, the receiver must be synchronized with DRC numbering and DRC. Since the method of synchronizing with the DRC numbering is illustrated in the above-mentioned part of FIG. 5, a detailed description thereof will be omitted.

After synchronizing with the DRC numbering, the receiver monitors the discovery channel in step 2420. The receiver (eg, D2D UE) may receive secure discovery information in the discovery channel.

Thereafter, in step 2430, the receiver may determine the information about the discovery channel logic time of the discovery channel carrying the discovery information. The determined discovery channel logical timing information may include a DRC number. In this case, according to an embodiment, the method may further include at least one of a discovery subframe number and a discovery physical channel index.

In operation 2440, the transmitter may generate a CRC using the security key, the determined discovery channel logic timing information, and the transmitted discovery information.

Specifically, referring to FIG. 23, the CRC generator 2310 may generate a CRC 2340 using the discovery PDU bit 2330, the security key 2320, and the CRC mask 2350. In this case, the CRC mask 2350 may include a discovery physical channel transmission time, that is, a DRC number and / or a discovery subframe number and / or a discovery physical channel index.

In operation 2450, the receiver may compare the generated CRC with the CRC received together with the discovery information from the transmitter.

At this time, the malicious UE may obtain the discovery PDU bit and generate a new CRC based on the new discovery physical channel transmission time. However, the malicious UE does not have a security key, so the CRC generated by the malicious UE will not be the same as the CRC generated by the receiver. In addition, even when the malicious UE plays the discovery PDU received without any change, the discovery CRC generated by the receiver is determined by the discovery CRC received because the discovery PDU transmission time transmitted by the malicious UE is different from the time when the discovery PDU is actually transmitted. It will differ from that by the PDU. Meanwhile, according to an embodiment, the discovery PDU bit may be composed of encrypted discovery information bits.

Looking at another method of CRC generation with reference to FIG. 25, the discovery PDU bit 2530 uses a security key 2520 and a one way security function (eg, an encryption function or a hash function) 2540. Can be modified. In this way, the modified discovery information or the modified discovery PDU bit 2570 may be generated. The modified discovery PDU bit 2570 may then be used to generate the CRC 2580 as shown in FIG. 23 above. That is, the CRC generator 2510 may generate the CRC 2580 using the modified discovery information or the modified discovery PDU bit 2570 and the CRC mask 2590. In this case, the CRC mask 2590 may include a discovery physical channel transmission time, that is, a DRC number and / or a discovery subframe number and / or a discovery physical channel index.

Thereafter, the discovery physical PDU 2550, including the raw discovery PDU bit 2530 that was modified and the generated discovery PDU CRC 2580, may be sent on the discovery physical channel. In this case, the modified discovery PDU bit 2570 is not transmitted on the discovery physical channel.

Referring to another method of generating a CRC with reference to FIG. 26, the discovery PDU bit 2630 may include a security key 2620 and a one-way security function (eg, an encryption function or a hash function) 2640. Can be modified using. In this way, the modified discovery information or the modified discovery PDU bit 2670 may be generated. The original, unmodified discovery PDU bit 2630 may then be used to generate the CRC 2680, as in the method illustrated in FIG. 23 above. That is, the CRC generator 2610 may generate the CRC 2680 using the unmodified discovery PDU bit 2630 and the CRC mask 2690. In this case, the CRC mask 2690 may include a discovery physical channel transmission time, that is, a DRC number and / or a discovery subframe number and / or a discovery physical channel index.

Thereafter, the discovery physical PDU 2650, including the modified discovery PDU bit 2670 and the generated discovery PDU CRC 2680, can be sent on the discovery physical channel. At this point, the unmodified raw discovery PDU bits 2630 are not transmitted on the discovery physical channel.

The reproduction protection method described above can be applied to any type of discovery as well as open and limited discovery. The security keys can be different for different cases, but the same method can be used. This method is generally applicable to the transmission and discovery of any information.

Fourth Embodiment CRC Generation Using Discovery Channel Logical Timing Information and Partial Absolute System Time Information

Synchronization of discovery resource and discovery resource cycle numbering, discovery subframe numbering, discovery physical channel numbering and discovery resource cycle numbering, related to discovery channel logical timing in the fourth embodiment are the same as illustrated in the first embodiment. Do.

Referring to the security key update trigger according to an embodiment of the present invention, the security key used by the transmitter and the receiver need not be updated by the UE participating in the discovery each time the DRC number rolls over.

According to this embodiment, this method is the same as that of <third embodiment> except that in addition to the discovery channel logic timing information, the discovery channel absolute system time information is also used. In addition, the partial absolute system time information may be determined by the transmitter and the receiver as described in the second embodiment. Therefore, a detailed description of the property protection method will be omitted.

In the fifth embodiment, the security key may be a symmetric key that the transmitter and receiver use equally. In another embodiment of the present invention, the security key may be an asymmetric key where the transmitter and receiver use different keys. According to an embodiment, a key pair consisting of a public key and a private key is used, where the private key is used by the transmitter and the public key can be used by the receiver. In the case of symmetric keys, the security algorithm generates a MAC, while in the case of asymmetric keys, the security algorithm generates a DS.

This method assumes that there is synchronization between the system frame and the absolute system time.

27 is a flowchart illustrating a method of securing discovery information in a transmitter according to an embodiment of the present invention, and FIG. 28 is a diagram illustrating a method of generating a MAC or DS according to an embodiment of the present invention.

Referring to FIG. 27, a transmitter (ie, a D2D UE) has discovery information that needs to be safely transmitted in a discovery channel. First, the transmitter synchronizes with the system frame and / or universal coordinated time corresponding to the system frame, if not already synchronized. Synchronization with the coordinated universal time corresponding to the system frame can be obtained by reading the system information transmitted by the BS carrying the coordinated universal time corresponding to the system frame number. Coordinated Universal Time represents an integer count in 10 ms units since 00:00:00 on January 1, 1900. Synchronization with the system frame number may be obtained by reading broadcast information carrying the system frame number. In this case, the broadcaster information is transmitted by the BS or the group leader. According to one embodiment, the system frame number may be transmitted by two parts by the base station. The first part carrying the MSB of the system frame number and the LSB of the system frame number may be transmitted in different broadcast information. For example, the system information block 'x' may carry LSBs of the system frame number, and the system information block 'y' may carry MSBs of the system frame number. The transmitter can read all of the system information to determine the system frame number. Alternatively, the D2D UE may determine the coordinated universal time from other sources, such as GPS, NITZ, or the like.

In an embodiment, the transmitter then transmits the system time of the system frame / discovery slot to which the discovery physical channel carrying the discovery information is transmitted (e.g., Coordinated Universal Time (UTC), i.e., January 1900). A system time counter that provides an integer count of 10 ms after 00:00:00) and / or information about the subframe number and / or the system frame number. In one embodiment, the system time or system time counter may be maintained in units of 10 ms, and a unique value of the system time or system time counter of each frame may be provided. Alternatively, the system time counter can be maintained in seconds. The system time counter may be initialized by the value of the coordinated universal time provided by the network (or obtained from GPS, NITZ, etc.). Alternatively, the system time counter may be initialized according to a value obtained from the value of the coordinated universal time provided by the network (or obtained from GPS, NITZ, etc.). For example, when the acquired system time is in units of 10 ms from 00:00:00 on January 1, 1900, the terminal may divide the value into 100 and set the system time counter to that value. For another example, when the acquired system time is in units of seconds from 00:00:00 on January 1, 1900, the terminal may set the system time to the value. The counters can be updated one per 100 frames. The system time or system time counter value may be the same for 100 frames. According to an alternative embodiment, the system time or system time counter may be maintained for other time units.

In addition, the system time and the system time counter may be used interchangeably within the present specification.

In one embodiment, the system time at which a discovery resource cycle (hereinafter referred to as a discovery cycle) starts may be determined instead of the system time of a system frame in which a discovery physical channel carrying discovery information is transmitted. The system time at which the discovery period begins may correspond to the system time of the first system frame of the discovery period. Alternatively, the system time at which the discovery period starts may correspond to the system time of the system frame corresponding to the first subframe of the discovery period.

The transmitter may then generate a message authentication code (MAC) or digital signature (DS) using the security key, the determined system time of the discovery channel and the discovery information to be transmitted in step 2720.

Specifically, according to an embodiment of the present invention, in addition to the security key and the discovery information to be protected, the system time of the discovery period of the discovery physical channel to which the discovery information to be protected is transmitted or the system time and / or sub-system of the system frame / discovery slot The frame number and / or system frame number may be provided to the security algorithm as illustrated in FIG. 28. The security algorithm then generates a MAC or DS. The generated MAC or DS may then be added to the discovery information. Depending on the embodiment, other parameters, such as the length of discovery information or the guild of the system time counter, etc. may also be provided to the security algorithm for generation of MAC or DS.

Meanwhile, according to an embodiment, the 'x' least significant bit of the system time used to generate a MAC or DS may be added to a header / tail of a PDU carrying discovery information. This can handle a situation where the receiving UE is in a different BS from the transmitting terminal and the BS timing of the receiving terminal is different from the timing of the transmitting terminal.

Thereafter, in operation 2730, the transmitter may transmit secure discovery information using a MAC or a DS in the discovery channel.

Referring to FIG. 29, first, a receiver synchronizes with a system frame and / or a coordinated universal time corresponding to the system frame when it is not already synchronized. Synchronization with the coordinated universal time corresponding to the system frame may be obtained by reading system information transmitted by the BS carrying the coordinated universal time corresponding to the system frame number. Coordinated Universal Time represents an integer count in 10 ms units since 00:00:00 on January 1, 1900. Synchronization with the system frame number may be obtained by reading broadcast information carrying the system frame number. In this case, the broadcaster information is transmitted by the BS or the group leader. According to one embodiment, the steam frame number may be transmitted by two parts by the base station. The first part carrying the MSB of the system frame number and the LSB of the system frame number may be transmitted in different broadcast information. For example, the system information block 'x' may carry LSBs of the system frame number, and the system information block 'y' may carry MSBs of the system frame number. The transmitter can read all of the system information to determine the system frame number. Alternatively, the D2D UE may determine the coordinated universal time from other sources corresponding to the system frame, for example GPS, NITZ, or the like.

In an embodiment, the receiver then monitors the discovery channel at step 2910 after synchronizing with the system frame and / or coordinated universal time corresponding to the system frame. The receiver (eg, D2D UE) may receive secure discovery information in the discovery channel.

In operation 2910, the receiver receives a system time or a system time counter of the system frame / discovery slot in which the discovery physical channel carrying the discovery information is received, that is, the time in Coordinated Universal Time (UTC), that is, January 1, 1900. (Integer count in units of 10 ms after 00:00) and / or information about the subframe number and / or the system frame number may be determined. In one embodiment, the system time or system time counter may be maintained in units of 10 ms, and a unique value of the system time or system time counter of each frame may be provided. Alternatively, the system time counter can be maintained in seconds. The system time counter may be initialized by the value of the coordinated universal time provided by the network (or obtained from GPS, NITZ, etc.). Alternatively, the system time counter may be initialized according to a value obtained from a coordinated universal time value provided by the network (or obtained from GPS, NITZ, etc.) for a particular system frame. For example, when the acquired system time is in units of 10 ms after 00:00:00 on January 1, 1900, the terminal may divide the value into 100 and set the system time counter to that value. For another example, when the acquired system time is in units of seconds after 00:00:00 on January 1, 1900, the terminal may set the system time to the value. The counters can be updated one per 100 frames. The system time or counter value may be the same for 100 frames. According to an alternative embodiment, the system time or system time counter may be maintained for other time units.

According to an embodiment, the 'x' least significant bits of system time may be received in the header / tail of the PDU carrying the discovery information. And, the receiver replaces the 'x' least significant bits of the system time determined according to the discovery information received using the system time maintained by the system time with the 'x' least significant bits of the received PDU, and this discovery information is Available as the system time of the discovery slot being received. Alternatively, the system time is along with the 'x' least significant bits that are closest to the system time in the receiving UE corresponding to the discovery slot where the discovery information is received and equal to the 'x' least significant bits received with the discovery message. May be used as the system time of the discovery slot being received.

Thereafter, in step 2920, the receiver may generate a MAC or DS using the security key, the system time of the determined system frame number, and the received discovery information.

Specifically, according to an embodiment of the present invention, in addition to the security key and the discovery information to be protected, the system time of the system frame / discovery slot of the discovery physical channel on which the discovery information to be protected is received, or the system time and / or sub of the discovery period The frame number and / or system frame number may be provided to the security algorithm as illustrated in FIG. 28. The security algorithm then generates a MAC or DS. The security algorithm can be executed at the receiver or at the D2D server. The receiver then receives the received information (MAC or DS and / or discovery subframe number (or frame number and subframe number), system time information and discovery information to the D2D server and / or sync / async). Identifier (sync: if the cell associated with the receiving terminal is synchronized with the transmitting terminal; async: if the cell associated with the receiving terminal is not synchronized with the transmitting terminal, alternatively sync / async may determine whether the transmitter is time synchronized with the receiver or not. May be instructed) to the D2D server.

The receiver may then compare the MAC or DS generated in step 2930 with the MAC or DS received with the discovery information from the transmitter. If a rogue sender plays a message, the system time of the frame that the receiver receives will be different from the time used to transmit by the genuine sender. This will result in failure of MAC or DS verification at the receiver.

According to an embodiment of the present invention, the receiver / D2D server is configured to 'determined system time of received discovery information' for MAC or DS validation-offset and 'determined system time of received discovery information' + You can use a value within the offset range. For example, the system time or system time counter corresponding to the frame in which discovery information is received is '1000', and the system time or system time counter may be maintained in units of seconds. And the offset may be two. The offset may be predetermined or signaled to the receiving terminal by the network. The receiver or the D2D server may use 999, 998, 1000, 1001 and 1002 for MAC or DS authentication as system time counter values. According to an embodiment, this method may be performed only when discovery information is received from the asycn cell. Similarly, for example, the system time corresponding to a discovery period in which discovery information is received is '1000', and the counter may be maintained in seconds. And the offset may be two. The offset may be predetermined or signaled to the receiving terminal by the network. The receiver or the D2D server may use 999, 998, 1000, 1001, and 1002 for MAC or DS authentication as system time counter values. According to an embodiment, this method may be performed only when discovery information is received from an asycn cell. In an alternative embodiment of this method, a discovery channel is a system frame number to which a discovery channel is transmitted and received and / or a subframe of a system frame. Logical timing may be used for the transmitter and receiver, respectively, in addition to the system time of the system frame or the system time of the discovery period or instead of the system time of the system frame / discovery period.

In this embodiment, no synchronization is made between the system frame and the absolute system time. In one embodiment of the present invention, the date of the packet transmission and the security key may be provided to the security algorithm to generate a MAC or DS as illustrated in FIG. This is useful if the discovery information does not change for one day. During the transition of day, a time window may be provided in which the received discovery information is ignored. This is done only if the day switch is not synchronized through the transmitting and receiving UE. In one embodiment, the date along with the AM or PM information may be used with a security key to generate a MAC or DS. This may allow the UE to update discovery information every half day. Alternatively, other parts of the day, such as a qtr period, may also be used with some timing windows between branch changes.

This embodiment is a case where there is no synchronization between the system frame and the absolute system time. In one embodiment of the present invention, discovery information may be transmitted periodically. The transmission period is more than the maximum time variation between the system times of the transmitting UE and the receiving UE. The system time at which the transmitter transmits the discovery information is encoded in the discovery PDU. If the receiving UE is within the receiving window, the receiving UE processes the discovery PDU. At this time, the receiving window is

a) System time + delta time of discovery PDU

b) System time of Discovery PDU-Delta time.

Delta time may include the difference in system time of transmitting and receiving UEs, processing time at the transmitter and receiver, and transmission time on the air interface.

Referring to FIG. 31, in another embodiment of the present invention, the network time received from the macro network may be used as a reference by both the transmitter and the receiver. The validity time (the time while discovery information is valid) can be used as one of the inputs along with keys and other parameters for MAC or DS calculation. The valid time will always be identified as the macro network time. The discovery message may carry a valid time. In an embodiment, the validity time may be used with the date for the calculation of MAC or DS as shown in FIG. In one embodiment, if the validity time and date are used in the calculation of the MAC or DS at the transmitter, the discovery message may also carry the validity time with an indicator to indicate the input of the date for the MAC computation.

Hereinafter, the security key generation method and update procedure will be described.

Security key for discovery (first method):

32 is a diagram illustrating a security key generation method according to an embodiment of the present invention, FIG. 33 is a flowchart illustrating a security key update method according to an embodiment of the present invention, and FIG. 34 is a diagram of the present invention. 35 is a flowchart illustrating a security key exchange method according to an embodiment, and FIG. 35 is a flowchart illustrating a security key exchange method according to another embodiment of the present invention, and FIG. 36 is yet another embodiment of the present invention. FIG. 37 is a flowchart illustrating a security key exchange method according to an embodiment, and FIG. 37 is a flowchart illustrating a security key reception method by a UE that receives discovery information according to an embodiment of the present invention.

One possible method of security key generation for open discovery is illustrated in FIG. 32. The UE supporting open discovery (send and receive) consists of a secret key KOD. Alternatively, after the UE is authorized to send and / or receive discovery information, the secret key KOD may be provided by the ProSe server or application server or authenticator. KOD is a common secret key for open discovery. The security key is stored in a secure location of the UE to prevent key leakage. The security key 'K' for reproduction protection / integrity protection of discovery information may be derived from the security key KOD using a security parameter.

The security parameter may include a random number (RAND) and a sequence number (SQN). In some embodiments, SQN may not be used. In some embodiments, other parameters such as security algorithm IDs may also be used additionally. K is not exchanged over the air. It is generated at the UE performing discovery. Security parameters, ie RAND and SQN, are generated at the ProSe server or MME. The playback protection 'K' may or may not be generated in the ProSe server or MME.

Update security parameters:

In one embodiment, the security parameters, ie RAND & SQN, may be updated per DRC number rollover by the ProSe server / MME. This ensures that the same key 'K' is not used across the DRC number rollover boundary. The updated security parameters, ie RAND and / or SQN, may be received by the UE from the ProSe server / MME in a unicast manner. Alternatively, according to an embodiment, the updated security parameters, ie RAND and / or SQN, may be broadcast by the ProSe server / MME via the base station and read by the UE participating in the discovery.

In one embodiment, the ProSe server may be timing synchronized with DRC timing and may generate new security parameters for each DRC number rollover. The MME may query the ProSe server before the DRC number rollover to ensure that security parameters are used after the DRC number rollover. Alternatively, the ProSe server can send the updated parameters to the MME without query.

In another embodiment, as shown in FIG. 33, ProSe server 3320 may not be synchronized with DRC timing, and MME 3310 may be new to ProSe server 3320 as in

steps

3350, 3355, and 3360. You can request security parameters. The MME 3310 may request the ProSe server 3320 for new security parameters in advance to allow sufficient time for the key update signal.

Thereafter, referring to FIG. 34, the MME 3430 uses the BS 3420 to establish these security parameters so that the UE 3410 participating in the discovery can read these parameters and use them to generate a key 'K'. You can broadcast the variable. That is, in step 3450, the MME 3430 may transmit security parameters to the BS 3420, and the BS 3420 received the security parameters may broadcast them to the UE 3410 in step 3451.

On the other hand, according to an embodiment, the updated security parameter set may also be indexed to prevent confusion between security parameters across the boundary of the DRC number rollover. The index can also be broadcast with security parameters.

In this way, the UE 3410 participating in the discovery reads the security parameters broadcast by the BS 3420 in step 3452 and generates a security key 'K' using the secret key KOD and the security parameters. Can be. The security key 'K' may then be used to send and receive open discovery information in the DRC. On the other hand, the security key index may be included in the discovery information by the UE transmitting the discovery information.

The UE 3410 participating in the discovery reads the security parameters broadcast by the BS 3420, updates the security key 'K', and uses the generated 'K' before DRC number rollover, The same security key 'K' may not be used during the DRC number rollover.

According to another embodiment of the present invention, referring to FIG. 35, only the security parameter index may be broadcast by the BS 3520 instead of the security parameter. That is, in step 3550, the MME 3530 may transmit the above-described security parameter index to the BS 3520, and in step 3551, the BS 3520 may broadcast the security parameter index to the UE 3510.

Thereafter, the UE 3510 participating in the discovery may query the ProSe server or MME 3530 for the updated security parameters. That is, in operation 3552, the UE 3510 may transmit a security key request message to the MME 3530, and in response thereto, the MME 3530 may transmit a security key response message to the UE 3510 in step 3553. At this time, the security key response message may include security key parameters, that is, RAND, SQN, security key index, and the like.

According to another embodiment of the present invention, referring to FIG. 36, BS 3620 may not broadcast any information about updated security parameters. In this case, the UE 3610 may query the MME or ProSe server 3630 for the security parameters if they do not have any security parameters. Thereafter, the UE 3610 participating in the discovery may query this when the DRC number rolls over.

In some embodiments, the security parameters (RAND / SQN / idx) may be specific to the BS or MME or MME group instead of the ProSe server.

In one embodiment of the invention, the KOD may be a common secret key for open discovery for all types of services. In another embodiment of the present invention, the KOD may be a common secret key specific to a particular service type. In this case, the service type may be indicated in the signaling procedure of FIGS. 33 to 36.

Security key for discovery (second method):

The UE supporting open discovery and transmitting discovery information is configured with a secret key KOD. KOD is a common secret key for open discovery. This common secret key is preconfigured in each UE capable of performing open discovery. Alternatively, after the UE is authorized to transmit discovery information, the secret key KOD may be provided by the ProSe server or application server or authenticator. The security key is stored in a secure location of the UE to prevent key leakage. The security key 'K' for reproduction protection / integrity protection of discovery information may be derived from the security key KOD by using the security parameter by the UE transmitting the discovery information as illustrated in FIG. 32.

Update security parameters:

In one embodiment, the security parameters, ie RAND & SQN, may be updated per DRC number rollover by the ProSe server / MME. This ensures that the same key 'K' is not used across the DRC number rollover boundary. The updated security parameters, ie RAND and / or SQN, may be received by the UE transmitting discovery information from the ProSe server / MME in a unicast manner. Alternatively, according to an embodiment, the updated security parameters, ie RAND and / or SQN, can be broadcast by the ProSe server / MME via the base station and read by the UE sending the discovery information.

steps

The MME can then broadcast this parameter via the BS so that the UE sending the discovery information can read this parameter and use it to generate a security key 'K'. According to an embodiment, the updated security parameter set may also be indexed to avoid confusion between security parameters across the boundary of the DRC number rollover. The index can also be broadcast with security parameters.

In this way, each UE sending discovery information reads the security parameters broadcast by the BS to generate a security key 'K' using the secret key KOD and the security parameters. The security key 'K' is then used to send open discovery information in the DRC. In addition, according to an embodiment, the security key index may be included in the discovery information by the UE transmitting the discovery information.

The UE sending the discovery information should read the security parameters broadcast by the BS, update the security key 'K' and not use the same security key 'K' during the DRC number rollover. Since this is similar to the contents described in the part related to FIG. 34, a detailed description thereof will be omitted.

In another embodiment of the present invention, only indexes may be broadcast by the BS instead of security parameters. Thereafter, the UE transmitting the discovery information may query the ProSe server or MME for the updated security parameter. Since this is similar to the contents described in the part related to FIG. 35, a detailed description thereof will be omitted.

In another embodiment of the present invention, the BS may not broadcast any information about the updated security parameters. In this case, the UE may query the MME or ProSe server for security parameters if it does not have any security parameters. The UE sending the discovery information will then query this when the DRC number rolls over. Since this is similar to the content described in the part related to FIG. 36, a detailed description thereof will be omitted.

In this way, the UE 3710 receiving the discovery information may query the MME / ProSe server 3730 to allow the security key 'K' to be used to receive the discovery information as illustrated in FIG. 37. The receiving UE 3710 does not have information about the secret key KOD, so a security key 'K' is delivered to the UE 3710. The receiving UE 3710 may request a new key 'K' before the DRC rolls over.

In one embodiment of the invention, the KOD may be a common secret key for open discovery for all types of services. In another embodiment of the present invention, the KOD may be a common secret key specific to a particular service type. In this case, the service type may be indicated in the signaling procedure of FIGS. 34 to 37.

In an alternate embodiment, the KOD may be specific to a UE transmitting discovery information, or the KOD may be specific to a UE transmitting discovery information and one or more UEs receiving discovery information. In this case, the receiving UE may request the ProSe server or the MME for a security key specific to the transmitting UE. The receiving UE may include the UE ID of the transmitting UE in the security key request. The transmitting UE may generate a security key and update it every rollover. The transmitting UE may then provide the security key to the MME or ProSe server using a secure connection. Alternatively, the transmitting UE's key may also be generated by the MME or ProSe server, and the transmitting UE may request it from the MME or ProSe server.

Security Key for Discovery (Third Method):

In this way, the secret key KOD is not configured or assigned to any UE. The UE transmitting the discovery information may request the security key 'K' from the MME or ProSe server or the application server. The security key 'K' is updated every DRC number rollover. If the network desires it can also be updated initially. The rest of the procedure is the same as in the second method.

Security features to protect discovery information are:

The security function implementing the above algorithm may be located in one of the following places.

ProSe PDCP Protocol Layer

2. Media Access Control Layer

3. Application layer

Sixth embodiment: encryption using discovery channel system time information

38 is a flowchart illustrating a method of securing discovery information in a transmitter according to an embodiment of the present invention, and FIG. 39 is a diagram illustrating an encryption method according to an embodiment of the present invention.

In this embodiment, it is assumed that there is synchronization between a system frame and an absolute system time.

Referring to FIG. 38, a transmitter (ie, a D2D UE) has discovery information that needs to be safely transmitted in a discovery channel. First, the transmitter synchronizes with the system frame and / or universal coordinated time corresponding to the system frame, if not already synchronized. Synchronization with the coordinated universal time corresponding to the system frame can be obtained by reading the system information transmitted by the BS carrying the coordinated universal time corresponding to the system frame number. Coordinated Universal Time represents an integer count in 10 ms units since 00:00:00 on January 1, 1900. Synchronization with the system frame number may be obtained by reading broadcast information carrying the system frame number. In this case, the broadcaster information is transmitted by the BS or the group leader. According to one embodiment, the steam frame number may be transmitted by two parts by the base station. The first part carrying the MSB of the system frame number and the LSB of the system frame number may be transmitted in different broadcast information. For example, the system information block 'x' may carry LSBs of the system frame number, and the system information block 'y' may carry MSBs of the system frame number. The transmitter can read all of the system information to determine the system frame number.

In an embodiment, the transmitter then transmits at step 3810 the system time of the system frame to which the discovery physical channel carrying the discovery information is transmitted (ie, an integer count in units of 10 ms after 00:00:00 on January 1, 1900). Information can be determined.

Thereafter, the transmitter may encrypt the discovery information using the security key, the determined system time of the discovery channel, and the discovery information to be transmitted in operation 3820.

Specifically, according to an embodiment of the present invention, in addition to the security key and the discovery information to be protected, the system time of the system frame or discovery period of the discovery physical channel through which the discovery information to be protected is transmitted is illustrated in FIG. 28. The same security algorithm can be provided. The security algorithm may then perform encryption of the discovery information.

In operation 3830, the transmitter may transmit encrypted discovery information in the discovery channel.

Referring to FIG. 40, first, a receiver synchronizes with a system frame and a coordinated universal time corresponding to the system frame when it is not already synchronized. This synchronization can be obtained by reading the system information transmitted by the BS carrying the coordinated universal time corresponding to the system frame number. Coordinated Universal Time represents an integer count in 10 ms units since 00:00:00 on January 1, 1900.

In an embodiment, the receiver then monitors the discovery channel in step 4010 after synchronizing with the system frame and the coordinated universal time corresponding to the system frame. The receiver (eg, a D2D UE) may receive encrypted discovery information in the discovery channel.

In operation 4010, the receiver receives information about a system time (that is, an integer count in units of 10 ms after 00:00:00 on January 1, 1900) in which a discovery physical channel carrying encrypted discovery information is received. Can be determined. In this embodiment, the receiver knows the discovery information that the receiver is interested in.

Thereafter, in step 4020, the receiver may encrypt discovery information (already available at the receiver) of interest to the receiver using the system time and security key of the system frame in which the discovery physical channel carrying the encrypted discovery information is received. have.

In operation 4030, the receiver may compare the generated encrypted discovery information with the received encrypted discovery information. If the two discovery information match, the receiver can find the discovery information that the receiver is interested in. On the other hand, if the two discovery information does not match, the receiver may discard the received discovery information. If the receiver discovers a plurality of discovery information, the receiver may encrypt each of the plurality of discovery information using a system time and a security key of a system frame in which a discovery physical channel carrying encrypted discovery information is received. The receiver may then compare the generated encrypted discovery information with the received encrypted discovery information.

According to an embodiment, one system frame number may include a plurality of subframes. Also in some embodiments, in addition to the system time of the system frame number, the subframe number may also be used to encrypt the discovery information.

For example, in one embodiment, the discovery information may include an application user ID. The transmitter with the application user ID1 may transmit discovery information. The transmitter may encrypt the discovery information using the system time of the system frame (eg, frame 'x') on which the discovery physical channel carrying the encrypted discovery information is transmitted or the system time of the discovery period and the security key. In this case, the receiver may discover friends of the application user ID1 and the application user ID2. The receiver may receive encrypted discovery information of the frame 'x'. In this case, the receiver may encrypt the application user ID2 using the system time of the system frame 'x' or the system time of the discovery period and the security key. The receiver can then compare the encrypted application user ID2 with the received encrypted discovery information. In this case, however, the two discovery information will not match. Thereafter, the receiver may encrypt the application user ID1 using the system time of the system frame 'x' or the system time of the discovery period and the security key. The receiver may then compare the encrypted application ID1 with the received encryption discovery information. In this case, the two discovery information will match, the receiver can know that the application user ID1 is in the discovery information, and the receiver can find a friend with the application user ID1.

If the encrypted discovery information is played back, the system frame number originally received by the transmitter and the system frame number received by the receiver will be different, and the matching result of the received discovery information and the encrypted application user ID1 by the receiver will fail.

According to an embodiment, the 'x' least significant bit of system time may be received in the header / tail of the PDU carrying the discovery information. And, the receiver may replace the 'x' least significant bit of the system time determined according to the discovery information received using the system time maintained by the system time with the 'x' least significant bit of the received PDU.

In an alternative embodiment, the discovery channel logical timing, which is the system frame number to which the discovery channel is transmitted and received and / or the subframe number of the system frame or the system time of the discovery period, is transmitted to the transmitter and the receiver in addition to the system time of the system frame / discovery period, respectively. Can be used.

In yet another alternative embodiment, the discovery channel logical timing, i.e., the DRC number and / or the discovery subframe number and / or the discovery physical channel index, may be used for each of the transmitter and receiver instead of the system time of the system frame.

In yet another alternative embodiment, the discovery logical timing, i.e., the system frame number and / or the subframe number of the subframe in which the discovery channel is transmitted / received, is determined by the system frame in the embodiments described in FIGS. Instead of system time, it can be used for transmitter and receiver respectively.

This embodiment may be useful when the receiver knows about discovery information of interest to him.

Depending on the embodiment, a one way hash function may be used in place of the security algorithm and the security key.

Referring to FIG. 41, in an embodiment, the UE may include a transceiver 4110 that transmits and receives a signal with another UE, BS, MME, or ProSe server. The controller 4120 may also include a controller 4120 that controls the transceiver 4110 to transmit and receive data and to process or determine data according to the transmitted and received data and a predetermined setting. In addition, the controller 4120 may control the terminal to perform any one of the above-described embodiments. In this case, the controller 4120 may synchronize with a discovery resource cycle number, for example, determine discovery channel logical timing information of a discovery physical channel to which discovery information is to be transmitted, a security key, and determine the discovery channel logical timing information and the transmission. Security information may be generated using discovery information to be transmitted, and the discovery information including the security information may be controlled to be transmitted through the discovery physical channel, but is not limited thereto. That is, the controller 4120 synchronizes with a discovery resource cycle number, receives discovery information including first security information in a discovery physical channel, and determines discovery channel logical timing information of the discovery physical channel in which the discovery information is received. The second security information may be generated using a security key, the determined discovery channel logical timing information, and the received discovery information, and the second security information may be controlled to verify the first security information and the second security information.

Referring to FIG. 42, the base station BS may include a transceiver 4210 that transmits and receives a signal with a UE, an MME, or a ProSe server. The control unit 4220 may include a control unit 4220 for transmitting and receiving data by controlling the transceiver and processing or determining data according to the transmitted and received data and a predetermined setting. In addition, the controller 4220 may control the base station to perform any one of the above-described embodiments.

The embodiments disclosed in the specification and the drawings are merely presented as specific examples to easily explain the technical contents and assist in understanding, and are not intended to limit the scope of the present invention. It will be apparent to those skilled in the art that other modifications based on the technical idea of the present invention can be carried out in addition to the embodiments disclosed herein.

On the other hand, the present specification and the drawings have been described with respect to the preferred embodiments of the present invention, although specific terms are used, it is merely used in a general sense to easily explain the technical details of the present invention and help the understanding of the invention, It is not intended to limit the scope of the invention. It will be apparent to those skilled in the art that other modifications based on the technical idea of the present invention can be carried out in addition to the embodiments disclosed herein.

Claims

In the terminal-to-terminal communication method of the transmitting terminal,

Synchronizing with a discovery resource cycle number;

Determining discovery channel logical timing information of a discovery physical channel to which discovery information is to be transmitted;

Generating security information using a security key, the determined discovery channel logical timing information, and discovery information to be transmitted; And

Transmitting the discovery information including the security information to the discovery physical channel;

Method of communication between terminals of the transmitting terminal comprising a.
According to claim 1,

The discovery channel logical timing information includes at least one of a discovery resource cycle number, a discovery subframe number, and a discovery physical channel index.
According to claim 1,

The security information includes at least one of a message authentication code (MAC) or a digital signature (DS).
According to claim 1,

The security information is a communication method between the terminals of the transmitting terminal, characterized in that it comprises a CRC (Cyclical Redundancy Check).
The method of claim 1, wherein the synchronizing is performed by:

Receiving a discovery resource cycle number associated with a discovery resource cycle from a base station; And

Synchronizing with the received discovery resource cycle number;

Method of communication between terminals of the transmitting terminal comprising a.
The method of claim 1, wherein the generating of the security information comprises:

Determining an absolute system time at which the discovery information is to be transmitted; And

Generating security information using a security key, the determined discovery channel logical timing information, the absolute system time and discovery information to be transmitted;

Method of communication between terminals of the transmitting terminal comprising a.
In the terminal-to-terminal communication method of the receiving terminal,

Synchronizing with a discovery resource cycle number;

Receiving discovery information including first security information in a discovery physical channel;

Determining discovery channel logical timing information of the discovery physical channel from which the discovery information is received;

Generating second security information by using a security key, the determined discovery channel logical timing information, and the received discovery information; And

Verifying the first security information and the second security information;

Method of communication between terminals of the receiving terminal comprising a.
The method of claim 7, wherein

The discovery channel logical timing information includes at least one of a discovery resource cycle number, a discovery subframe number, and a discovery physical channel index.
The method of claim 7, wherein

And the first security information and the second security information include at least one of a message authentication code (MAC) or a digital signature (DS).
The method of claim 7, wherein

And the first security information and the second security information include a CRC (Cyclical Redundancy Check).
The method of claim 7, wherein the synchronizing process,

Receiving a discovery resource cycle number associated with a discovery resource cycle from a base station; And

Synchronizing with the received discovery resource cycle number;

Method of communication between terminals of the receiving terminal comprising a.
The method of claim 7, wherein the generating of the second security information comprises:

Determining an absolute system time at which the discovery information was received; And

Generating security information using a security key, the determined discovery channel logical timing information, the absolute system time and discovery information to be transmitted;

Method of communication between terminals of the transmitting terminal comprising a.
In the terminal-to-terminal communication method of the transmitting terminal,

Determining a system time and system frame of a system frame or discovery slot corresponding to a discovery physical channel to which discovery information is to be transmitted;

Generating security information using a security key, the determined system time and the discovery information to be transmitted; And

Transmitting the discovery information including the security information to the discovery physical channel;

Method of communication between terminals of the transmitting terminal comprising a.
The method of claim 13,

Synchronizing with a universal coordinated time corresponding to the system frame;

Method of communication between the terminals of the transmitting terminal further comprises.
In the terminal-to-terminal communication method of the receiving terminal,

Receiving discovery information including first security information in a discovery physical channel;

Determining a system time and a system frame of a discovery frame or a system frame corresponding to the discovery physical channel through which discovery information is transmitted;

Generating second security information using a security key, the determined system time and the transmitted discovery information; And

Verifying the first security information and the second security information;

Method of communication between terminals of the receiving terminal comprising a.
The method of claim 15,

Synchronizing with a universal coordinated time corresponding to the system frame;

Method of communication between the terminals of the transmitting terminal further comprises.
A transmitting terminal that supports communication between terminals,

Communication unit for communicating with the other terminal and the base station; And

Synchronize with a discovery resource cycle number, determine discovery channel logical timing information of a discovery physical channel to which discovery information is to be transmitted, generate security information using a security key, the determined discovery channel logical timing information, and discovery information to be transmitted, A control unit controlling to transmit the discovery information including the security information to the discovery physical channel;

Transmission terminal comprising a.
The method of claim 17,

The discovery channel logical timing information includes at least one of a discovery resource cycle number, a discovery subframe number, and a discovery physical channel index.
The method of claim 17,

The security information includes at least one of a message authentication code (MAC) or a digital signature (DS).
The method of claim 17,

The security information is characterized in that it comprises a Cyclic Redundancy Check (CRC).
The method of claim 17, wherein the control unit,

Receiving from the base station a discovery resource cycle number associated with a discovery resource cycle, and controlling to synchronize with the received discovery resource cycle number.
The method of claim 17, wherein the control unit,

Determine an absolute system time for transmitting the discovery information, and control to generate security information using a security key, the determined discovery channel logical timing information, the absolute system time, and discovery information to be transmitted. A transmitting terminal.
In a receiving terminal that supports communication between terminals,

Communication unit for communicating with the other terminal and the base station; And

Synchronize with a discovery resource cycle number, receive discovery information including first security information on a discovery physical channel, determine discovery channel logical timing information of the discovery physical channel on which the discovery information was received, and determine a security key, the determined discovery A controller configured to generate second security information by using channel logical timing information and the received discovery information and to verify the first security information and the second security information;

Receiving terminal comprising a.
The method of claim 23, wherein

The discovery channel logical timing information includes at least one of a discovery resource cycle number, a discovery subframe number, and a discovery physical channel index.
The method of claim 23, wherein

And the first security information and the second security information include at least one of a message authentication code (MAC) or a digital signature (DS).
The method of claim 23, wherein

The first security information and the second security information receiving terminal characterized in that it comprises a Cyclic Redundancy Check (CRC).
The method of claim 23, wherein the control unit,

Receiving a discovery resource cycle number associated with a discovery resource cycle from a base station, and controlling to synchronize with the received discovery resource cycle number.
The method of claim 23, wherein the control unit,

Determine an absolute system time at which the discovery information was received, and control to generate security information using a security key, the determined discovery channel logical timing information, the absolute system time, and discovery information to be transmitted; A receiving terminal.
A transmitting terminal that supports communication between terminals,

Communication unit for communicating with the other terminal and the base station; And

Determine a system time and system frame of a system frame or discovery slot corresponding to a discovery physical channel to which discovery information is to be transmitted, generate security information using a security key, the determined system time, and the discovery information to be transmitted, and A control unit controlling to transmit the discovery information including the information to the discovery physical channel;

Transmission terminal comprising a.
The method of claim 29, wherein the control unit,

And control to synchronize with a coordinated universal time corresponding to the system frame.
The method of claim 29, wherein the control unit,

And control to synchronize with a coordinated universal time corresponding to the system frame.
The method of claim 32, wherein the control unit,

And controlling to synchronize with a coordinated universal time corresponding to the system frame.