CN102833681A - Method and system for configuring PWS (public warning system) key information in wireless communication system - Google Patents

Abstract

The invention discloses a method and a system for configuring PWS (public warning system) key information in a wireless communication system. The method comprises the following steps that: a CBC (cell broadcast center) sends a message for key distribution to a network entity in the wireless communication system, wherein the message carries PWS key information; and after receiving the message for key distribution, the network entity in the wireless communication system stores the PWS key information in the message. The PWS comprises the CBC and a first network entity, wherein the CBC is used for sending the PWS key information to the first network entity; and the first network entity is used for storing the PWS key information. The invention provides a specific scheme of how to obtain PWS key information by the network entity distributing the PWS key information to UE (user equipment), thereby laying a foundation for obtaining the PWS key information from a network by virtue of the UE so as to realize the safety protection of the PWS.

Description

Method and system for configuring public alarm system key information in wireless communication system

technical field

The present invention relates to the field of communications, in particular to a method and system for network configuration of a public warning system (Public Warning System, PWS) key in a wireless communication system.

Background technique

In order to enable users to receive alarms, warnings and key information about disasters and other emergencies in a timely and accurate manner, 3GPP (3rd Generation Partnership Project, 3rd Generation Partnership Project) defines the PWS service. During disasters such as earthquakes, tsunamis, hurricanes and wildfires, the business empowers the public to take appropriate action to protect themselves and their families from serious injury or death, or significant property damage.

Different communication networks defined by 3GPP, such as GSM (Global System of Mobilecommunication, Global System for Mobile Communications), UMTS (Universal MobileTelecommunications System, Universal Mobile Communications System) and LTE (Long TermEvolution, long-term evolution) all support PWS services, It is also stipulated that the PWS service is carried and sent by CBS (CellBroadcast Service, cell broadcast service). Its architecture is shown in Figure 1, and the functions of each network entity are described as follows:

Cell Broadcast Entity (CBE for short): It does not belong to the communication network defined by 3GPP. CBE is responsible for formatting CBS (Cell Broadcast Service, Cell Broadcast Service), including dividing CBS messages into different pages.

Cell Broadcast Center (CBC for short): It is part of the core network and can be connected to multiple CBEs. CBC is responsible for the management of CBS messages, including: determining the time when CBS messages start broadcasting; determining the time when CBS messages stop broadcasting, and instructing each BSC/RNC to stop broadcasting CBS messages; determining the time interval for CBS messages to be repeatedly broadcast; determining the broadcast CBS The cell broadcast channel of the message, etc. For the GSM network, the CBC is connected to the BSC (Base Station Controller, base station controller) located in the wireless access network; for the UMTS system, the CBC is connected to the RNC (Radio Network Controller, wireless network controller) located in the wireless access network through the Iu interface. controller); for the LTE system, the CBC is connected to the MME (Mobility Management Entity, Mobility Management Entity) of the core network. After CBC receives the alarm information sent by CBE, it configures and encapsulates it, and sends it to BSC (GSM system), RNC (UMTS system), MME (LTE system) in the affected area, and BSC/RNC/MME forwards it to the base station (GSM system is BTS, UMTS system is NB, LTE system is eNB) broadcast to users.

The currently defined CBS services are all sent on the broadcast channel. Currently, broadcast channels do not have any security protection. An attacker can tamper with an alert message or, upon receipt, replay it in another unaffected area, causing unnecessary panic and confusion among the public. In order to prevent this from happening, PWS can be protected safely, that is, by using digital signature fields and time stamps, and introducing signature algorithms and key management schemes. After the terminal receives the broadcast alarm message, it will first authenticate the message, and only when the authentication is successfully passed, can it be sure that it is a valid alarm message.

For any signature-based authentication scheme, the verifier needs to obtain the signer's public key or other symmetric key used to authenticate the message, and needs to ensure that the key is valid. That is, for the UE, the network needs to send the key of the PWS service to the UE. To this end, the network needs to pre-configure the key and related information of the PWS service. After the UE successfully accesses the network, it can obtain PWS key information. In this way, when a disaster occurs, the CBC can directly broadcast the alarm information sent by the CBE to the UE through the 3GPP network. At the same time, if the PWS needs to update the key of the PWS service regularly or irregularly, it also needs to send the updated key information of the PWS service to each network entity, and then each network entity sends it to the UE.

In the current 3GPP specification, how the network entity that distributes the PWS key information to the UE obtains the PWS key information is still a problem to be solved.

Contents of the invention

The technical problem to be solved by the present invention is to provide a method and system for configuring PWS key information in a wireless communication system.

In order to solve the above problems, the present invention provides a method for configuring public warning system (PWS) key information in a wireless communication system, including:

The cell broadcast center (CBC) sends the PWS key information to the network entity in the wireless communication system;

A network entity in the wireless communication system stores the PWS key information.

Preferably,

The PWS key information includes the key of the PWS service, and the key of the PWS service is a public key used for signing, or other symmetric keys used for authenticating messages.

Preferably,

The CBC sends PWS key information to the network entity in the wireless communication system, including:

The CBC sends a message for key distribution to a network entity in the wireless communication system, carrying the PWS key information;

The network entity in the wireless communication system saves the PWS key information, including:

After receiving the message for key distribution, the network entity in the wireless communication system saves the PWS key information therein.

Preferably,

The CBC sends a message for key distribution to a network entity in the wireless communication system, which is triggered by the following conditions:

The CBC decides to perform network configuration of the PWS service; or

The CBC decides to update the PWS key information sent to the network entity.

Preferably,

The network entity in the wireless communication system is one or more of the following network entities: Mobility Management Entity (MME); Serving GPRS Support Node (SGSN); Mobile Switching Center (MSC); Radio Network Controller (RNC) ; and a base station controller (BSC).

Preferably,

The CBC sends PWS key information to the network entity in the wireless communication system, including:

The CBC sends a message for key distribution to a mobile management entity (MME), carrying the PWS key information;

After receiving the message for key distribution sent by the CBC, the MME sends a message for key distribution to an evolved Node B (eNB), carrying the PWS key information;

The network entity in the wireless communication system saves the PWS key information, including:

After receiving the message for key distribution sent by the MME, the eNB saves the PWS key information therein.

Preferably,

The CBC sends PWS key information to the network entity in the wireless communication system, including:

The CBC sends an alarm request message to a network entity in the wireless communication system, carrying the alarm content to be broadcast by the CBC to the user and the PWS key information;

The network entity in the wireless communication system saves the PWS key information, including:

The network entity in the wireless communication system extracts and saves the PWS key information from the received alarm request message.

Preferably,

The network entities in the wireless communication system are one or more of the following network entities: Mobility Management Entity (MME), Radio Network Controller (RNC) and Base Station Controller (BSC).

Preferably,

The CBC sends an alert request message to a network entity in the wireless communication system, which is triggered by the following conditions: the CBC receives an alert message sent by a Cell Broadcast Entity (CBE), and decides to send PWS key information at the same time or decides to update an existing PWS key information sent to network entities.

Preferably,

The PWS key information includes: the current key of the PWS service, and one or more of the key identifier, key serial number, key life cycle, and PWS signature algorithm corresponding to the current key.

Preferably,

The PWS key information also includes: the next one or more keys of the PWS service, and for each key, the key identification, key serial number, key life cycle and PWS key corresponding to the key are also included. One or more of the signature algorithms.

Correspondingly, the present invention also provides a public warning system (PWS) in a wireless communication system, which includes a cell broadcast center (CBC) and a first network entity, wherein:

The CBC is used to send PWS key information to the first network entity;

The first network entity is used to save the PWS key information.

Preferably,

The PWS key information sent by the CBC includes the key of the PWS service, and the key of the PWS service is a public key used for signing, or other symmetric keys used for authenticating messages.

Preferably,

The CBC implements sending the PWS key information to the first network entity by sending a message for key distribution to the first network entity and carrying the PWS key information in the message;

The PWS key information saved by the first network entity is extracted from the received message for key distribution.

Preferably,

The CBC sends a message for key distribution to the first network entity, which is triggered by the following conditions: the CBC decides to perform network configuration of the PWS service; or, the CBC decides to update the PWS key that has been sent to the network entity. key information.

Preferably,

The first network entity is one or more of the following network entities: Mobility Management Entity (MME), Serving GPRS Support Node (SGSN), Mobile Switching Center (MSC), Radio Network Controller (RNC) and base station control Controller (BSC).

Preferably,

The wireless communication system is a Long Term Evolution (LTE) system, the first network entity is an evolved Node B (eNB) in the LTE system, and the public warning system further includes a Mobility Management Entity (MME) in the LTE system;

The CBC sends the PWS key information to the eNB by sending a message for key distribution to the MME and carrying the PWS key information in the message;

The MME is configured to, after receiving the message for key distribution sent by the CBC, send a message for key distribution to the eNB, carrying the PWS key information;

The PWS key information saved by the eNB is extracted from the received message for key distribution sent by the MME.

Preferably,

The first network entity is one or more of the following network entities: Mobility Management Entity (MME), Radio Network Controller (RNC) and Base Station Controller (BSC);

The CBC implements sending the PWS key information to the first network entity by sending an alarm request message to the first network entity and carrying the PWS key information in the alarm request message;

The PWS key information saved by the first network entity is extracted from the received alarm request message.

The present invention also provides a public warning system (PWS) in a wireless communication system, including a cell broadcast center (CBC) and a serving GPRS support node (SGSN), wherein:

The CBC has a first interface connected to the SGSN, and the CBC transfers PWS key information to the SGSN through the first interface.

Preferably,

The public alert system also includes Mobile Switching Centers (MSC);

The CBC also has a first interface connected to the MSC, and the CBC transmits PWS key information to the MSC through the first interface.

The above method and system propose a specific scheme of how the network entity that distributes the PWS key information to the UE obtains the PWS key information, laying a foundation for the UE to obtain the PWS key information from the network and realize the security protection of the PWS.

Description of drawings

The accompanying drawings described here are used to provide a further understanding of the present invention and constitute a part of the application. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations to the present invention.

FIG. 1 shows a network architecture diagram of an existing PWS in a 3GPP network;

FIG. 2 shows a schematic diagram of sending PWS key information to MME in an LTE network according to Embodiment 1 of the present invention;

Fig. 3 shows a schematic diagram of sending PWS key information to SGSN or MSC in UMTS or GSM network according to Embodiment 2 of the present invention;

FIG. 4 shows a schematic diagram of sending PWS key information to eNB in an LTE network according to Embodiment 3 of the present invention;

FIG. 5 shows a schematic diagram of sending PWS key information to RNC or BSC in UMTS or GSM network according to Embodiment 4 of the present invention;

Fig. 6 shows a schematic diagram of sending PWS key information together with an alarm message to an MME or RNC or BSC in an LTE or UMTS or GSM network according to Embodiment 5 of the present invention.

Fig. 7 shows a PWS security architecture diagram in a GSM network and a UMTS network, including a description of an interface added to a CBC network element.

Detailed ways

In order to make the purpose, technical solution and advantages of the present invention more clear, the embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings. It should be noted that, in the case of no conflict, the embodiments in the present application and the features in the embodiments can be combined arbitrarily with each other.

Embodiment one

This embodiment shows the process of CBC sending PWS key information to MME in LTE network. The steps are as follows:

1) CBC triggers the PWS key information sending process.

The trigger condition includes: the CBC decides to configure the network of the PWS service, or the CBC decides to update the PWS key information sent to the network entity, etc.

2) The CBC sends a message for key distribution to the MME, and the message carries a parameter: PWS key information.

In this embodiment, the above-mentioned message used for key distribution is a key distribution message, and other embodiments also use the key distribution message as an example, but the present invention may also use other message names.

The PWS key information includes the key of the PWS service, which may be a public key used for signing, or other symmetric keys used for authenticating messages.

For example, in one example, the PWS key information includes: the current key of the PWS service, and one or more of the key identifier, key serial number, key life cycle, and PWS signature algorithm corresponding to the current key . Optionally, the PWS key information also includes: the next one or more keys of the PWS service (that is, one or more keys used after the current key), and for each key, the key One or more of the key ID, key serial number, key life cycle, and PWS signature algorithm corresponding to the key.

3) The MME stores the received PWS key information.

4) The MME sends a key distribution confirmation message to the CBC, and confirms to the CBC that it has received the PWS key information.

Correspondingly, this embodiment also provides a public alarm system in a wireless communication system, including a cell broadcast center (CBC) and MME, wherein:

The CBC is used to send a message for key distribution to the MME and carry PWS key information in the message, the PWS key information includes the key of the PWS service, and the key of the PWS service is used for signing Public key, or other symmetric key used to authenticate messages.

The MME is configured to extract and save the PWS key information from the received message for key distribution.

Further, the CBC sends a message for key distribution to the first network entity, which may be triggered by the following conditions: the CBC decides to perform the network configuration of the PWS service; or, the CBC decides to update the information sent to the network entity. PWS key information.

Embodiment two

In this embodiment, an interface for PWS key distribution is added between CBC and SGSN or MSC, through which CBC sends PWS key information to SGSN and/or MSC in UMTS network, or in GSM/EDGE network SGSN and/or MSC.

The steps for this sending process are described below:

1) CBC triggers the PWS key information sending process. The trigger condition includes: the CBC decides to configure the network of the PWS service, or the CBC decides to update the PWS key information sent to the network entity, etc.

2) The CBC sends a key distribution message to the SGSN and/or MSC, and the message carries a parameter: PWS key information.

The PWS key information includes the key of the PWS service, which may be a public key used for signing, or other symmetric keys used for authenticating messages.

For example, in one example, the PWS key information includes: the current key of the PWS service, and one or more of the key identifier, key serial number, key life cycle, and PWS signature algorithm corresponding to the current key . Optionally, the PWS key information also includes: the next one or more keys of the PWS service, and for each key, the key identification, key serial number, and key life cycle corresponding to the key are also included. and one or more of the PWS signature algorithms.

3) SGSN and/or MSC store the received PWS key information.

4) The SGSN and/or MSC send a key distribution confirmation message to the CBC to confirm to the CBC that they have received the PWS key information.

Correspondingly, this embodiment also provides a public warning system in a wireless communication system, including a cell broadcast center (CBC), and SGSN and/or MSC, wherein:

The CBC is used to send a message for key distribution to the SGSN and/or MSC and carry PWS key information in the message, the PWS key information includes the key of the PWS service, and the key of the PWS service is The public key used for signing, or other symmetric keys used to authenticate messages.

The SGSN and/or MSC is used to extract and save the PWS key information from the received message for key distribution.

Further, the CBC sends a message for key distribution to the SGSN and/or MSC, which may be triggered by the following conditions: the CBC decides to perform the network configuration of the PWS service; or, the CBC decides to update the information sent to the network entity PWS key information.

Embodiment three

This embodiment shows the process of CBC sending PWS key information to eNB in LTE network. The steps are as follows:

1) CBC triggers the PWS key information sending process. The trigger condition includes: the CBC decides to configure the network of the PWS service, or the CBC decides to update the PWS key information sent to the network entity, etc.

2) The CBC sends a key distribution message to the MME, and the message carries a parameter: PWS key information.

The PWS key information includes the key of the PWS service, which may be a public key used for signing, or other symmetric keys used for authenticating messages.

For example, in one example, the PWS key information includes: the current key of the PWS service, and one or more of the key identifier, key serial number, key life cycle, and PWS signature algorithm corresponding to the current key . Optionally, the PWS key information also includes: the next one or more keys of the PWS service, and for each key, the key identification, key serial number, and key life cycle corresponding to the key are also included. and one or more of the PWS signature algorithms.

3) The MME sends a key distribution message to the eNB, and the message carries a parameter: PWS key information, which may be the same as the PWS key information in step 2).

4) The eNB stores the received PWS key information.

5) The eNB sends a key distribution confirmation message to the MME, and confirms to the MME that it has received the PWS key information

6) The MME sends a key distribution confirmation message to the CBC, and confirms to the CBC that the eNB has received the PWS key information.

Correspondingly, this embodiment also provides a public alarm system in a wireless communication system, including a cell broadcast center (CBC), eNB and MME, wherein:

The CBC is used to send a message for key distribution to the MME and carry the PWS key information in the message;

The MME is configured to, after receiving the message for key distribution sent by the CBC, send the message for key distribution to the eNB and carry the PWS key information;

The eNB is configured to extract and save the PWS key information from the received message for key distribution sent by the MME.

Further, the CBC sends a message for key distribution to the SGSN and/or MSC, which may be triggered by the following conditions: the CBC decides to perform the network configuration of the PWS service; or, the CBC decides to update the information sent to the network entity PWS key information.

Embodiment four

This embodiment shows the process of the CBC sending the PWS key information to the RNC in the UMTS network, or the BSC in the GSM/EDGE network.

The steps are as follows:

1) CBC triggers the PWS key information sending process. The trigger condition includes: the CBC decides to configure the network of the PWS service, or the CBC decides to update the PWS key information sent to the network entity, etc.

2) The CBC sends a key distribution message to the RNC and/or BSC, and the message carries a parameter: PWS key information.

The PWS key information includes the key of the PWS service, which may be a public key used for signing, or other symmetric keys used for authenticating messages.

For example, in one example, the PWS key information includes: the current key of the PWS service, and one or more of the key identifier, key serial number, key life cycle, and PWS signature algorithm corresponding to the current key . Optionally, the PWS key information also includes: the next one or more keys of the PWS service, and for each key, the key identification, key serial number, and key life cycle corresponding to the key are also included. and one or more of the PWS signature algorithms.

3) RNC and/or BSC store the received PWS key information.

4) The RNC and/or BSC send a key distribution confirmation message to the CBC, confirming to the CBC that they have received the PWS key information.

Correspondingly, this embodiment also provides a public alarm system in a wireless communication system, including a cell broadcast center (CBC), and RNC and/or BSC, wherein:

The CBC is used to send a message for key distribution to the RNC and/or BSC and carry PWS key information in the message, the PWS key information includes the key of the PWS service, and the key of the PWS service is The public key used for signing, or other symmetric keys used to authenticate messages.

The RNC and/or BSC are configured to extract and save the PWS key information from the received message for key distribution.

Further, the CBC sends a message for key distribution to the first network entity, which may be triggered by the following conditions: the CBC decides to perform the network configuration of the PWS service; or, the CBC decides to update the information sent to the network entity. PWS key information.

Embodiment five:

This embodiment shows that the CBC carries the PWS key information in the alarm request message, and sends them together to the MME in the LTE network, or the RNC in the UMTS network, or the BSC in the GSM/EDGE network.

The steps for this process are described below:

1) CBC triggers the PWS key information sending process. The trigger condition includes: the CBC receives the alarm message sent by the CBE, decides to send the PWS key information at the same time or decides to update the PWS key information sent to the network entity, etc.

2) The CBC sends an alarm request message to the MME or RNC or BSC, which includes the content of the alarm to be broadcast by the CBC to the user and the PWS key information.

The PWS key information includes the key of the PWS service, which may be a public key used for signing, or other symmetric keys used for authenticating messages.

For example, in one example, the PWS key information includes: the current key of the PWS service, and one or more of the key identifier, key serial number, key life cycle, and PWS signature algorithm corresponding to the current key . Optionally, the PWS key information also includes: the next one or more keys of the PWS service, and for each key, the key identification, key serial number, and key life cycle corresponding to the key are also included. and one or more of the PWS signature algorithms.

3) The MME or RNC or MSC extracts and stores the PWS key information from the received alarm request message.

4) The MME or RNC or MSC sends an alarm confirmation message to the CBC to confirm to the CBC that it has received the alarm message.

Correspondingly, this embodiment also provides a public alarm system in a wireless communication system, including a cell broadcast center (CBC), and a first network entity, where the first network entity may be one of MME, RNC, and MSC or more, of which:

The CBC is used to send an alarm request message to the first network entity and carry the PWS key information in the alarm request message;

The first network entity is configured to extract and save the obtained PWS key information from the received alarm request message.

Further, the CBC sends the alarm request message to the first network entity, which is triggered by the following conditions: the CBC receives the alarm message sent by the CBE, and decides to send the PWS key information at the same time or decides to update it to the network entity PWS key information.

It is easy to understand that although each of the above embodiments takes a specific wireless communication system as an example, the CBC can also send the above-mentioned network entities in multiple wireless communication systems (such as one of the MME, MSC, SGSN, BSC, and RNC) at the same time. or more) to send the PWS key information. At this point, the multiple wireless communication systems can be regarded as a large wireless communication system including multiple wireless communication systems.

Embodiment six

This embodiment shows a PWS security architecture diagram in a GSM network, a UMTS network and an LTE network, including a description of an interface added to a CBC network element, as shown in FIG. 7 .

In the figure, the CBE and the CBC exchange PWS information through interface 1. As a network element of the core network, the CBC has an interface Iu _BC with the BSC of the GSM network and the RNC of the UMTS network, and has an interface S1 _BC with the MME of the LTE network, and is used to transmit PWS content information. In addition, an Iu _CBC interface is added to the CBC network element, which is connected to the SGSN and/or MSC through this interface, and used to transmit PWS key information to the SGSN and/or MSC.

Those skilled in the art can understand that all or part of the steps in the above method can be completed by instructing relevant hardware through a program, and the program can be stored in a computer-readable storage medium, such as a read-only memory, a magnetic disk or an optical disk, and the like. Optionally, all or part of the steps in the above embodiments can also be implemented using one or more integrated circuits. Correspondingly, each module/unit in the above embodiments can be implemented in the form of hardware, or can be implemented in the form of software function modules. The form is realized. The present invention is not limited to any specific combination of hardware and software.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (20)

1. A method for configuring public warning system (PWS) key information in a wireless communication system, comprising: The cell broadcast center (CBC) sends the PWS key information to the network entity in the wireless communication system; A network entity in the wireless communication system stores the PWS key information. 2. The method of claim 1, wherein: The PWS key information includes the key of the PWS service, and the key of the PWS service is a public key used for signing, or other symmetric keys used for authenticating messages. 3. The method of claim 1, wherein: The CBC sends PWS key information to the network entity in the wireless communication system, including: The CBC sends a message for key distribution to a network entity in the wireless communication system, carrying the PWS key information; The network entity in the wireless communication system saves the PWS key information, including: After receiving the message for key distribution, the network entity in the wireless communication system saves the PWS key information therein. 4. The method of claim 1, wherein: The CBC sends a message for key distribution to a network entity in the wireless communication system, which is triggered by the following conditions: The CBC decides to perform network configuration of the PWS service; or The CBC decides to update the PWS key information sent to the network entity. 5. The method according to claim 3 or 4, characterized in that: The network entity in the wireless communication system is one or more of the following network entities: Mobility Management Entity (MME); Serving GPRS Support Node (SGSN); Mobile Switching Center (MSC); Radio Network Controller (RNC) ; and a base station controller (BSC). 6. The method of claim 1, wherein: The CBC sends PWS key information to the network entity in the wireless communication system, including: The CBC sends a message for key distribution to a mobile management entity (MME), carrying the PWS key information; After receiving the message for key distribution sent by the CBC, the MME sends a message for key distribution to an evolved Node B (eNB), carrying the PWS key information; The network entity in the wireless communication system saves the PWS key information, including: After receiving the message for key distribution sent by the MME, the eNB saves the PWS key information therein. 7. The method of claim 1, wherein: The CBC sends PWS key information to the network entity in the wireless communication system, including: The CBC sends an alarm request message to a network entity in the wireless communication system, carrying the alarm content to be broadcast by the CBC to the user and the PWS key information; The network entity in the wireless communication system saves the PWS key information, including: The network entity in the wireless communication system extracts and saves the PWS key information from the received alarm request message. 8. The method of claim 7, wherein: The network entities in the wireless communication system are one or more of the following network entities: Mobility Management Entity (MME), Radio Network Controller (RNC) and Base Station Controller (BSC). 9. The method according to claim 7 or 8, characterized in that: The CBC sends an alert request message to a network entity in the wireless communication system, which is triggered by the following conditions: the CBC receives an alert message sent by a Cell Broadcast Entity (CBE), and decides to send PWS key information at the same time or decides to update an existing PWS key information sent to network entities. 10. The method of claim 1 or 3 or 6 or 7, characterized in that: The PWS key information includes: the current key of the PWS service, and one or more of the key identifier, key serial number, key life cycle, and PWS signature algorithm corresponding to the current key. 11. The method of claim 9, wherein: The PWS key information also includes: the next one or more keys of the PWS service, and for each key, the key identification, key serial number, key life cycle and PWS key corresponding to the key are also included. One or more of the signature algorithms. 12. A public warning system (PWS) in a wireless communication system, characterized in that it comprises a cell broadcast center (CBC) and a first network entity, wherein: The CBC is used to send PWS key information to the first network entity; The first network entity is used to save the PWS key information. 13. The public alert system of claim 12, wherein: The PWS key information sent by the CBC includes the key of the PWS service, and the key of the PWS service is a public key used for signing, or other symmetric keys used for authenticating messages. 14. The public alert system of claim 12, wherein: The CBC implements sending the PWS key information to the first network entity by sending a message for key distribution to the first network entity and carrying the PWS key information in the message; The PWS key information saved by the first network entity is extracted from the received message for key distribution. 15. The public alert system of claim 12, wherein: The CBC sends a message for key distribution to the first network entity, which is triggered by the following conditions: the CBC decides to perform network configuration of the PWS service; or, the CBC decides to update the PWS key that has been sent to the network entity. key information. 16. A public warning system as claimed in claim 14 or 15, characterized in that: The first network entity is one or more of the following network entities: Mobility Management Entity (MME), Serving GPRS Support Node (SGSN), Mobile Switching Center (MSC), Radio Network Controller (RNC) and base station control Controller (BSC). 17. The public alert system of claim 12, wherein: The wireless communication system is a Long Term Evolution (LTE) system, the first network entity is an evolved Node B (eNB) in the LTE system, and the public warning system further includes a Mobility Management Entity (MME) in the LTE system; The CBC sends the PWS key information to the eNB by sending a message for key distribution to the MME and carrying the PWS key information in the message; The MME is configured to, after receiving the message for key distribution sent by the CBC, send a message for key distribution to the eNB, carrying the PWS key information; The PWS key information saved by the eNB is extracted from the received message for key distribution sent by the MME. 18. The public alert system of claim 12, wherein: The first network entity is one or more of the following network entities: Mobility Management Entity (MME), Radio Network Controller (RNC) and Base Station Controller (BSC); The CBC implements sending the PWS key information to the first network entity by sending an alarm request message to the first network entity and carrying the PWS key information in the alarm request message; The PWS key information saved by the first network entity is extracted from the received alarm request message. 19. A public warning system (PWS) in a wireless communication system, comprising a cell broadcast center (CBC) and a serving GPRS support node (SGSN), characterized in that: The CBC has a first interface connected to the SGSN, and the CBC transfers PWS key information to the SGSN through the first interface. 20. The public alert system of claim 19, wherein: The public alert system also includes Mobile Switching Centers (MSC); The CBC also has a first interface connected to the MSC, and the CBC transmits PWS key information to the MSC through the first interface.

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