CN101309503A - Wireless handover method, base station and terminal - Google Patents

Abstract

The invention relates to the field of wireless communication, discloses a wireless switching method, a base station and a terminal, and improves the security of the terminal when performing wireless switching. In the present invention, the target base station encrypts the security information and terminal capability information independently of the source base station, and sends the encrypted information to the terminal through the source base station. When the terminal capability information received matches the terminal capability , using the received security information to switch to the target base station. The pseudo key of the target base station can be stored in the source base station in advance, the source base station carries the pseudo key of the target base station to the target base station in the handover request, and the target base station decrypts the pseudo key to obtain the shared key with the terminal. The target base station may also directly obtain the shared key with the terminal from the MME when receiving the handover request.

Description

Wireless handover method, base station and terminal

technical field

The invention relates to the field of wireless communication, in particular to switching technology.

Background technique

With the gradual development of communication, people's requirements for mobile communication are getting higher and higher, and the existing network architecture and protocols of the 3rd Generation Partnership Project (3GPP for short) can no longer meet the needs of users for mobile communication. Therefore, 3GPP proposed a concept of an evolved network that serves future communication requirements.

In order to ensure the competitiveness of the 3GPP system in the next 10 years or even longer, especially to strengthen the ability of the 3GPP system to handle the rapidly growing IP data services, 3GPP started the Long Term Evolution (LTE) from the second half of 2004 "LTE") project, and the System Architecture Evolution ("SAE") project.

The LTE evolution system consists of three parts: Evolved Radio Access Network (Evolved Radio Access Network, referred to as "E-RAN"), Evolved Packet Core Network (Evolved Packet Core, referred to as "EPC") and terminals.

Among them, the evolved packet core network mainly includes: Mobility Management Entity (MME for short), User Plane Entity (UPE for short), 3GPP Anchor (3GPP Anchor) and packet data network access Gateway (Packet Data Network Gateway, referred to as "PDN GW").

The evolved radio access network mainly includes an evolved base station (eNB). The terminal accesses the core network through the evolved base station (hereinafter referred to as the base station). In the LTE system, the terminal also needs to switch between base stations when it is moving. In addition, since the base station is relatively vulnerable to attacks in the LTE system, it becomes insecure. Therefore, in the LTE system, during the handover process of the terminal between the base stations, it is necessary to transmit information between the terminal and the base station, and between the handover base stations. The information is protected and the security independence between base stations is enhanced. The security-related network elements in the LTE system are shown in Figure 1. These network elements form two security layers: security layer 1 and security layer 2. Moreover, the interfaces between these network elements, such as the Xu interface and X2 interface between the base stations, and the S1-C and S1-U interfaces between the base station and the MME and UPE all have security requirements.

In prior art 1, the flow of handover of a terminal from a source base station to a target base station is shown in FIG. 2 .

In step 201, the source base station sends a measurement control message to the terminal.

In step 202, the terminal sends a measurement report to the source base station.

In step 203, when the measurement report received by the source base station reaches a threshold value, the source base station decides to initiate a handover operation to the target base station according to the measurement report.

In step 204, the source base station sends a handover request to the target base station, and the request message includes information such as terminal capabilities and keys. The key may be a key currently shared by the source base station with the terminal, or a key derived from the current shared key, or a key newly derived by the MME.

In step 205, after receiving the handover request, the target base station performs admission control to determine whether the terminal can be handed over to the base station, and if the terminal is allowed to handover to the base station, the process proceeds to step 206.

In step 206, the target base station selects content such as a security algorithm according to the capabilities of the terminal to form a context (CONTEXT), and sends a handover request confirmation message to the source base station through the X2 interface, and carries the CONTEXT containing the security algorithm in the handover request confirmation message sent to the source base station. The sending process may pass the security protection of X2.

In step 207, the source base station sends a handover command to the terminal, and forwards the security algorithm selected by the target base station and other indication information (such as relevant security parameters) that the target base station needs to notify the terminal to the terminal in the handover command. The current key and algorithm are used for protection between the source base station and the terminal. In addition, the source base station may also forward the cached data packets belonging to the terminal and data packets currently being sent to the terminal to the target base station, and the target base station sends these data packets.

In step 208, after receiving the handover command, the terminal disconnects from the source base station and establishes uplink synchronization with the target base station.

In step 209, the target base station sends uplink resource allocation and timing advance to the terminal.

In step 210, after receiving the uplink resource allocation and timing advance of the target base station, a handover confirmation message is sent to the target base station. Starting from this message including the sending of this message, the key and algorithm agreed upon by the target base station and the terminal can be used to protect the information sent between the two.

In step 211, the target base station sends a handover completion message to the core network MME.

In step 212, the MME sends a handover completion confirmation message to the target base station.

In step 213, after receiving the handover completion confirmation message, the target base station sends a radio resource release message to the source base station, notifying the source base station to release resources.

In step 214, the source base station forwards the downlink data not sent to the terminal to the target base station, and releases the radio resources allocated for the terminal after the forwarding is completed.

In the above process, the relevant steps involving the establishment of security parameter association between the target base station and the terminal are steps 204 , 206 , 207 and 210 . When the terminal initiates communication with the target base station after completing the handover, a shared session key has been obtained between the terminal and the target base station. In the above process, the shared key between the terminal and the target base station can be generated based on the existing shared key between the terminal and the source base station; or, if the MME participates in the handover, the target base station can also obtain a new key shared with the terminal from the MME. key. For example, the terminal is communicating with base station 1 and shares a key with base station 1. If the terminal switches to base station 2, the terminal and base station 2 can derive a shared key by using the key shared with base station 1. That is, the shared key of the terminal and base station 2 is derived from the shared key of the terminal and base station 1 . The method of deriving the shared key between the terminal and the target base station from the existing shared key between the terminal and the source base station may include three methods shown in FIG. 3: the source key (the shared key between the terminal and the source base station) and The target key (the shared key between the terminal and the target base station) is derived from the same root key; or, the source key is derived from the root key, and the source key derives the target key; or, the source key is directly used as the target key.

However, the inventors of the present invention found that in the above situation, if the base station 1 (ie, the source base station) has security risks, the key of the base station 2 (ie, the target base station) will also be affected and become insecure. This is the domino effect that can occur when a terminal is handed over to another base station. Specifically, the following problems may exist:

1) If the source base station is controlled by an attacker, the ability of the source base station to tamper with the terminal may occur, causing the terminal to use a weak security algorithm or not use a security algorithm after switching, resulting in a BIDDING DOWN (security downgrade) attack.

2) If the X2 interface has a security risk, the attacker may tamper with the signaling exchanged on the X2 interface, which may also cause the terminal to use a weak security algorithm or not use a security algorithm after switching, resulting in a BIDDINGDOWN (security downgrade) attack.

The second prior art is improved on the basis of the first prior art, and the main steps are as follows.

Step 1: When the source base station sends a handover request message to the target base station, the handover request message includes the session key content (Session Key Context, referred to as "SKC") shared by the terminal and the target base station. SKC is composed of three members: IDBSV, EK_SN-C_BSV{SKUEk_BSV, KCT}, and MACK_SN-C_BSV. IDBSV refers to the identity of the target base station, EK_SN-C_BSV is the key shared by the core network with the target base station and the terminal, and KCT is the source The base station and the target base station share a secret key, and MACK_SN-C_BSV is the message authentication code between the core network and the target base station.

Step 2: When the target base station responds to the source base station with a handover confirmation, it transmits information indicating the terminal such as the selected security algorithm. KCT may be used for protection when transmitting to the source base station.

Step 3: The source base station forwards the target base station's algorithm and related security parameters to the terminal, and the source base station and the terminal are protected by the current key and algorithm.

Step 4: The terminal sends a handover confirmation to the target base station.

However, the inventors of the present invention have found that in the above handover method, if the source base station is controlled by an attacker, the source base station may modify the capabilities of the terminal, which will also cause the terminal to use a weak security algorithm or not use a security algorithm after handover, resulting in BIDDING DOWN attack.

Contents of the invention

The main technical problem to be solved by the embodiments of the present invention is to provide a wireless handover method, a base station and a terminal, so that the security of the terminal is improved when performing wireless handover.

In order to solve the above technical problems, the embodiment of the present invention provides a wireless handover method, which is applied to a wireless communication system for performing security protection processing on signaling and/or user data in a base station, including the following steps:

The target base station encrypts the security information and terminal capability information independently of the source base station, and sends the encrypted information to the terminal through the source base station;

When the received terminal capability information matches the terminal capability, the terminal uses the received security information to switch to the target base station.

Embodiments of the present invention also provide a base station, including a security protection unit, configured to perform security protection processing on signaling and/or user data, including:

The encryption unit is used to encrypt the terminal capability information of the terminal to be handed over to the base station and the security information to be used by the security protection unit independently of the source base station;

The sending unit is configured to send the information encrypted by the encryption unit to the terminal through the source base station.

Embodiments of the present invention also provide a terminal, including:

a receiving unit, configured to receive security information and terminal capability information from the target base station;

a decryption unit, configured to decrypt the security information and terminal capability information received by the receiving unit in a manner independent of the source base station;

A comparison unit, configured to compare the terminal capability information obtained by the decryption unit with the terminal capability;

The processing unit is configured to use the security information obtained by the decryption unit to perform handover processing to the target base station when the comparison unit judges that the terminal capability information matches the terminal capability.

Compared with the prior art, the embodiment of the present invention has the main difference and its effects in that:

The target base station encrypts the information that needs to be forwarded by the source base station in a manner independent of the source base station, thereby effectively preventing the maliciously controlled source base station from tampering with relevant information; the target base station encrypts the terminal capability information obtained from the source base station After sending to the terminal, the terminal compares the received terminal capability information with its own capability, and can know whether the terminal capability information obtained by the target base station has been tampered with, so that it can take targeted measures when the terminal capability information has been tampered with, effectively improving It improves the security of the terminal during wireless switching.

Description of drawings

FIG. 1 is a schematic diagram of security-related network elements in an LTE system in the prior art;

FIG. 2 is a flowchart of a handover of a terminal from a source base station to a target base station in the prior art;

FIG. 3 is a schematic diagram of three alternative schemes for key derivation when switching between a source base station and a target base station in the prior art;

FIG. 4 is a flowchart of a wireless handover method according to a first embodiment of the present invention;

5 is a flowchart of a wireless handover method according to a second embodiment of the present invention;

Fig. 6 is a structural diagram of a wireless handover system according to a fourth embodiment of the present invention.

Detailed ways

In order to make the purpose, technical solution and advantages of the present invention clearer, the following will further describe the implementation of the present invention in detail in conjunction with the accompanying drawings.

The first embodiment of the present invention relates to a wireless handover method, which is applied to a wireless communication system, such as an LTE system, in which a base station performs security protection processing on signaling and/or user data.

The specific process is shown in Figure 4. In step 401, the source base station decides to initiate handover according to the measurement report sent by the terminal.

In step 402, the source base station sends a handover request message to the target base station, and the handover request message carries the pseudo-key of the target base station obtained from the MME in advance, the capability information of the terminal, and the like.

Specifically, the pseudo-key refers to the encrypted base station key (that is, the shared key between the base station and the terminal), which can only be obtained by deciphering the base station to which the key belongs. In this embodiment, the MME carries the pseudo key of the neighboring base station of the source base station while delivering the key to the source base station. In this step, after the source base station determines which adjacent base station to handover the terminal to, that is, after determining the target base station, it carries the pseudo key belonging to the target base station and the capability information of the terminal in the handover request message and sends it to the target base station. It can be seen that in this implementation manner, the source base station cannot decrypt the fake key to obtain the key of the target base station, so the security of the key of the target base station is better guaranteed.

In step 403, after receiving the handover request message, the target base station obtains the pseudo key of the base station, and decrypts the pseudo key to obtain the shared key between the target base station and the terminal. Ability to choose a security algorithm.

In step 404, the target base station uses the shared key (that is, the shared key between the target base station and the terminal) to encrypt and/or integrity protect the security information and the capability information of the terminal. The security information here includes the security algorithm selected by the target base station.

To be precise, this step is to use the shared key to encrypt and/or integrity protect part or all of the content that the target base station needs to transmit to the terminal but that the source base station does not need to parse. The content mentioned here includes security algorithms and terminal Capability information or radio resource control (Radio Resource Controller, "RRC") CONTAINER (RRC container), etc.

Since the shared key is known by the terminal but not known by the source base station, by using the shared key to encrypt and/or integrity-protect some or all of the content that needs to be transmitted to the terminal but does not need to be parsed by the source base station, it can ensure This part of the content cannot be tampered with by the source base station during the subsequent forwarding process, so even if the source base station is controlled by the attacker, it will not cause a BIDDING DOWN attack.

In step 405, the target base station sends the encrypted security information and terminal capability information to the source base station through the X2 interface between the base stations, and is protected by the X2 security protocol during the sending process.

In step 406, the source base station sends a handover command to the terminal, carries the encrypted security information and capability information of the terminal in the handover command and sends it to the terminal.

In step 407, after receiving the handover command, the terminal derives the shared key between the terminal and the target base station from the local root key according to information such as the identity of the target base station, and uses the derived shared key to pair the received Decrypt the information to obtain the security information and terminal capability information sent by the target base station to the terminal, and compare the decrypted terminal capability information with the terminal capability, if the decrypted terminal capability information matches the terminal capability, go to step 408 ; Conversely, if it does not match, go to step 409.

In step 408, the terminal uses the decrypted security information to switch to the target base station. Specifically, the terminal can use the shared key and the decrypted security algorithm to send a handover confirmation message to the target base station; after receiving it, the target base station also uses the shared key and the security algorithm to return a handover completion message to the terminal, and Send a terminal location update message to the MME.

In step 409, the decrypted terminal capability information does not match the terminal capability, and the terminal notifies the source base station of handover failure, and the notification carries failure reason information indicating that the received terminal capability information does not match the actual terminal capability.

In step 410, after receiving the notification of the handover failure, the source base station resends a handover request message to the target base station.

It can be seen that in this embodiment, the target base station encrypts the information that needs to be forwarded by the source base station in a manner independent of the source base station, thereby effectively preventing the maliciously controlled source base station from tampering with relevant information; The base station encrypts the terminal capability information obtained from the source base station and sends it to the terminal. The terminal compares the received terminal capability information with its own capability to know whether the terminal capability information obtained by the target base station has been tampered with. Taking targeted measures when tampered with effectively improves the security of the terminal during wireless switching.

The second embodiment of the present invention also relates to a wireless handover method, which is roughly the same as the first embodiment. The difference is that in the first embodiment, the pseudo key of the target base station is stored in the source base station in advance, and the source base station transmits When a handover request is made, the pseudo-key of the target base station is sent to the target base station in the handover request, and the target base station decrypts the pseudo-key to obtain a shared key with the terminal. In this way, the target base station does not need to Specifically obtain the shared key with the terminal from the MME, which reduces message interaction and shortens the handover delay; and in this embodiment, the target base station directly obtains the shared key with the terminal from the MME when receiving the handover request, because It is obtained directly, which reduces the possibility of the shared key being cracked by being forwarded by an unreliable source base station.

The specific process is shown in FIG. 5. In step 501, the source base station decides to initiate handover according to the measurement report sent by the terminal.

In step 502, the source base station sends a handover request message to the target base station, and the handover request message carries terminal capability information and the like.

In step 503, after receiving the handover request message, the target base station obtains the shared key between the target base station and the terminal from the MME.

In step 504, the target base station selects a security algorithm according to the capability of the terminal.

In step 505, the target base station uses the shared key (that is, the shared key between the target base station and the terminal) to encrypt and/or integrity protect the security information and the capability information of the terminal. The security information here includes the security algorithm selected by the target base station.

In this step, some or all of the content that the target base station needs to transmit to the terminal and that the source base station does not need to parse is encrypted and/or integrity protected using the shared key. The content mentioned here includes security algorithms and terminal capability information Or radio resource control (Radio Resource Controller, referred to as "RRC") CONTAINER (RRC container), etc.

Since the shared key is obtained from the MME, it is also known by the terminal but not known by the source base station. Therefore, by using the shared key, some or all of the content that needs to be transmitted to the terminal but does not need to be parsed by the source base station is encrypted and/or Integrity protection can ensure that this part of the content cannot be tampered with by the source base station during the subsequent forwarding process, so that even if the source base station is controlled by the attacker, it will not cause BIDDING DOWN attacks.

Steps 506 to 511 are completely the same as steps 405 to 410 , and will not be repeated here.

The third embodiment of the present invention also relates to a wireless handover method, which is roughly the same as the first or second embodiment, and the difference is that in the first or second embodiment, the target base station directly transfers the encrypted secure The information and the capability information of the terminal are sent to the source base station, and the source base station forwards it to the terminal. Since the target base station and the source base station can communicate directly, the communication efficiency is high; and in this embodiment, the target base station sends the encrypted security information and the capability information of the terminal is sent to the equipment in the core network, which is sent to the source base station by the equipment (such as MME) in the core network, and then sent to the terminal by the source base station. The target base station and the source base station can also communicate through the relay of MME and other equipment in the core network, which has a wider range of adaptability, and is especially suitable for situations where there is no X2 interface between the target base station and the source base station, such as cross-MME handover.

In the above several embodiments, the shared key between the target base station and the terminal is used to encrypt the security information and terminal capability information to be sent to the terminal. It should be noted that in the above embodiments, it is also possible to Encrypt the security information and terminal capability information using a key known to other terminals but unknown to the source base station. As long as the encryption is independent of the source base station, it can effectively prevent the maliciously controlled source base station from accessing relevant information. tampering.

The fourth embodiment of the present invention relates to a wireless handover system, which is applied to a wireless communication system, such as an LTE system, that performs security protection processing on signaling and/or user data in a base station. As shown in FIG. 6, the wireless handover system includes a source base station, a target base station and a terminal. Wherein the target base station includes: a security protection unit, which is used to perform security protection processing on signaling and/or user data; The information is encrypted independently of the source base station; the sending unit is configured to send the information encrypted by the encryption unit to the terminal through the source base station. Wherein, the security information includes a security algorithm. Since the target base station encrypts the information that needs to be forwarded by the source base station in a manner independent of the source base station, it effectively prevents the maliciously controlled source base station from tampering with relevant information.

The sending unit can directly send the encrypted information to the source base station through the X2 interface, and forward it to the terminal through the source base station. This method has high communication efficiency; the sending unit can also send the encrypted information to the core network. The equipment (such as MME) is sent by the equipment in the core network to the source base station, and then sent to the terminal by the source base station. This method has wider adaptability, especially suitable for the X2 interface between the target base station and the source base station. situation, such as the situation of inter-MME handover.

The base station may also include a first receiving unit, configured to receive a handover request from the source base station, where the handover request includes a pseudo-key of the base station; a decryption unit, configured to decrypt the pseudo-key received by the first receiving unit Decrypt to obtain the shared key between the base station and the terminal; the encryption unit uses the shared key deciphered by the decryption unit to encrypt the security information and terminal capability information. In this manner, the target base station does not need to obtain the shared key with the terminal from the MME during handover, which reduces message interaction and shortens handover delay.

Alternatively, the base station may further include a second receiving unit, configured to obtain the shared key between the target base station and the terminal from the MME; the encryption unit uses the shared key obtained by the second receiving unit to encrypt the security information and terminal capability information . By directly obtaining the shared key, the possibility of the shared key being cracked by being forwarded by an unreliable source base station is reduced.

The terminal includes: a receiving unit for receiving security information and terminal capability information from the target base station; a decryption unit for decrypting the security information and terminal capability information received by the receiving unit in a manner independent of the source base station; comparing A unit for comparing the terminal capability information obtained by the decryption unit with the terminal capability; a processing unit for using the security information obtained by the decryption unit when the comparison unit determines that the terminal capability information obtained by decryption matches the terminal capability Handover to the target base station is performed. By comparing the received terminal capability information with its own capability, it is possible to know whether the terminal capability information obtained by the target base station has been tampered with, so that targeted measures can be taken when the terminal capability information has been tampered with, effectively improving the terminal's wireless security. Security when switching.

The terminal may also include a key derivation unit, configured to derive a shared key between the terminal and the target base station from a local root key according to the information of the target base station; the decryption unit uses the shared key generated by the key derivation unit to decrypt.

The terminal may also include a failure notification unit, configured to notify the source base station of handover failure when the comparison unit determines that the decrypted terminal capability information does not match the terminal capability. Information about the failure reason of terminal capability mismatch.

To sum up, in the embodiment of the present invention, the target base station encrypts the information that needs to be forwarded by the source base station in a manner independent of the source base station, thereby effectively preventing the maliciously controlled source base station from tampering with relevant information; The target base station encrypts the terminal capability information obtained from the source base station and sends it to the terminal. The terminal compares the received terminal capability information with its own capability to know whether the terminal capability information obtained by the target base station has been tampered with. Taking targeted measures when the information is tampered with effectively improves the security of the terminal during wireless switching.

The pseudo key of the target base station can be stored in the source base station in advance, the source base station carries the pseudo key of the target base station to the target base station in the handover request, and the target base station decrypts the pseudo key to obtain the shared key with the terminal. In this manner, the target base station does not need to obtain the shared key with the terminal from the MME during handover, which reduces message interaction and shortens handover delay.

The target base station can also directly obtain the shared key with the terminal from the MME when receiving the handover request, because it is obtained directly, which reduces the possibility of the shared key being cracked by being forwarded by an unreliable source base station.

The target base station and the source base station can communicate directly through the X2 interface, and the communication efficiency is high; the target base station and the source base station can also communicate through the transfer of MME and other equipment in the core network, which has a wider range of adaptation, especially for the target base station The case where there is no X2 interface with the source base station, such as the case of inter-MME handover.

Although the present invention has been illustrated and described with reference to certain preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the present invention. The spirit and scope of the invention.

Claims (16)

1. wireless switching method is applied in the base station signaling and/or user data are carried out the wireless communication system of safe protection treatment, it is characterized in that, may further comprise the steps:

Target BS is independent of the encryption of source base station to security information and terminal ability information, and the information after encrypting is sent to terminal by described source base station;

Described terminal uses the security information of being received to switch to described target BS when the terminal ability information of being received and this terminal capability coupling.

2. wireless switching method according to claim 1 is characterized in that described wireless communication system is a long evolving system.

3. wireless switching method according to claim 2 is characterized in that, and is further comprising the steps of before the step of described encryption:

Described source base station sends handoff request to described target BS, wherein carries in advance the pseudo-key of the described target BS that obtains from mobile management entity;

The pseudo-key that described target BS carries described handoff request is decrypted, and obtains the shared key of this target BS and terminal;

In the step of described encryption, described target BS uses the shared key of described target BS and terminal that described security information and terminal ability information are encrypted.

4. wireless switching method according to claim 2 is characterized in that, and is further comprising the steps of before the step of described encryption:

Described source base station sends handoff request to described target BS,

Described target BS obtains the shared key of this target BS and described terminal from mobile management entity;

In the step of described encryption, described target BS uses the shared key of described target BS and terminal that security information and terminal ability information are encrypted.

5. wireless switching method according to claim 1, it is characterized in that, during in the terminal ability information of being received and this terminal capability coupling, use the security information of being received to switch to before the step of described target BS in described terminal, further comprising the steps of:

Described terminal derives from into the shared key of this terminal and described target BS from the root key of this locality according to the information of described target BS;

Described terminal uses derivative shared key that the information of receiving is decrypted, and obtains security information and terminal ability information;

Described terminal is relatively deciphered the terminal ability information that obtains and whether this terminal capability mates.

6. wireless switching method according to claim 5 is characterized in that, and is further comprising the steps of after described comparison step:

If described terminal ability information and described terminal capability do not match, then described terminal is notified described source base station handoff failure, carries terminal ability information and the unmatched failure cause information of physical end ability that expression is received in the notice.

7. wireless switching method according to claim 1, it is characterized in that, information after described will the encryption sends in the end step by described source base station, information after described target BS will be encrypted by and described source base station between interface send to this source base station, be forwarded to described terminal by this source base station.

8. wireless switching method according to claim 1, it is characterized in that, information after described will the encryption sends in the end step by described source base station, information after described target BS will be encrypted sends to the equipment in the core net, send to described source base station by the equipment in the core net, send to described terminal by this source base station again.

9. wireless switching method according to claim 1 is characterized in that described security information comprises security algorithm.

10. a base station comprises security protection unit, is used for signaling and/or user data are carried out safe protection treatment, it is characterized in that, comprising:

Ciphering unit is used for the terminal ability information of the terminal that will switch to this base station and security information that described security protection unit need be used are independent of the encryption of source base station;

Transmitting element is used for the information after encrypting through described ciphering unit is sent to terminal by described source base station.

11. base station according to claim 10 is characterized in that, described base station is the base station in the long evolving system.

12. base station according to claim 10 is characterized in that, also comprises first receiving element, is used to receive the handoff request from described source base station, comprises the pseudo-key of this base station in this handoff request;

Decrypting device is used for the pseudo-key that described first receiving element is received is decrypted, and obtains the shared key of this base station and described terminal;

The shared key that described ciphering unit uses described decrypting device to solve is encrypted described security information and terminal ability information.

13. base station according to claim 10 is characterized in that, also comprises second receiving element, is used for obtaining from mobile management entity the shared key of this target BS and described terminal;

The shared key that described ciphering unit uses described second receiving element to obtain is encrypted described security information and terminal ability information.

14. a terminal is characterized in that, comprising:

Receiving element is used for security information and the terminal ability information of reception sources from target BS;

Decrypting device, the security information and the terminal ability information that are used for described receiving element is received are decrypted in the mode that is independent of source base station;

Comparing unit is used for terminal ability information and this terminal capability that more described decrypting device obtains;

Processing unit is used for when described comparing unit is judged described terminal ability information and this terminal capability coupling, and the security information of using described decrypting device to obtain is carried out to described target BS switching processing.

15. terminal according to claim 14 is characterized in that, comprises that also the key derivation unit is used for deriving from into from the root key of this locality according to the information of described target BS the shared key of this terminal and described target BS;

The shared key that described decrypting device uses described key derivation unit to generate carries out described deciphering.

16. according to claim 14 or 15 described terminals, it is characterized in that, also comprise the failure notification unit, be used for when described comparing unit judges that described terminal ability information and this terminal capability do not match, notify described source base station handoff failure, carry terminal ability information and the unmatched failure cause information of physical end ability that expression is received in the notice.

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