WO2011147153A1

WO2011147153A1 - Method and system for enabling access stratum (as) security algorithm synchronization

Info

Publication number: WO2011147153A1
Application number: PCT/CN2010/077955
Authority: WO
Inventors: 王波; 李静岚
Original assignee: 中兴通讯股份有限公司
Priority date: 2010-05-27
Filing date: 2010-10-21
Publication date: 2011-12-01
Also published as: CN102264064A

Abstract

The present invention discloses a method and system for enabling Access Stratum (AS) security algorithms synchronization and protection. Said method includes: during the Radio Resource Control (RRC) connection re-establishment procedure, the E-UTRAN Node B (eNB) informs the UE of whether refreshing the AS security algorithms or not, and if the AS security algorithms needs to be refreshed, the algorithms configuration cell is carried in the RRC Connection Re-establishment message to carry the AS security algorithms; according to the information, the UE implements the integrity protection and the encryption on the RRC Re-establishment Complete message by adopting the corresponding AS security algorithms; according to the AS security algorithms configured locally, the eNB decrypts the RRC Re-establishment Complete message and verifies its integrity, and determines whether to start the security acknowledgement according to the AS security algorithms adopted currently. The method and system disclosed by the present invention can prevent the AS security algorithms from being juggled during the RRC Connection Re-establishment procedure, and avoid the bandwidth waste caused by the invalid air interface data packets, and further improve the user experience during the handover procedure.

Description

Method and system for realizing access layer security algorithm synchronization

The present invention relates to a Long Term Evolution (LTE) technology, and more particularly to a method and system for synchronizing an access layer security algorithm when RRC connection reestablishment occurs after switching. Background technique

At present, in the Long Term Evolution (LTE) system, due to the highly decentralized geographical location and logical structure of the evolved Node B (eNB, E-UTRAN Node B), the operator cannot perform centralized security control on the eNB. Each eNB is in a non-secure zone.

The eNB needs to select its own access layer (AS, Access Stratum) security algorithm according to its specific situation and the security capabilities of the user equipment (UE, User Equipment).

The basic principle of the AS security algorithm selection is: the security capability information of the UE is sent to the eNB through the signaling process (for example, the core network carries the security capability of the UE to the eNB in the initial context setup request message), and the eNB supports the UE and the UE. The AS security algorithm intersection, select a highest priority AS security algorithm. When a handover occurs, the eNB needs to update the AS security algorithm according to the above principles, and inform the UE of the new AS security algorithm through the air interface message.

Each eNB needs to maintain its own AS security parameters (including algorithms and keys) with the UE. Obviously, the support of the AS security algorithm by each eNB is not necessarily the same. When the cross-eNB handover occurs, if the UE handover fails, the UE may initiate a radio resource control (RRC) connection re-establishment (RRC) connection again at the target side eNB. At this time, if the target side eNB does not support the UE, The original AS security algorithm causes the AS security algorithm to be out of synchronization. Figure 1 is a schematic diagram of the process of causing the AS security algorithm to be out of synchronization during the RRC connection reestablishment process in the prior art. As shown in Figure 1, specifically:

It is assumed that the security algorithm supported by eNB1 is not supported by eNB2, then, when the UE is switched If the eNB connection fails to be reestablished to the eNB2 when the eNB2 fails (such as the RRC reconfiguration at the time of handover), if the UE does not perform the AS security algorithm selection according to the AS security algorithm supported by the eNB2, the original AS security algorithm is still used. (ie, the security algorithm supported by eNB1), if the RRC re-establishment complete message is integrity-protected and encrypted, eNB2 must generate a failure to decrypt and integrity check the message because it does not support the original security algorithm, and finally cause the UE to switch. The subsequent access fails, which seriously affects the user's perception.

For the problem that the AS layer security algorithm is not synchronized due to the fact that the AS security algorithm is not updated when the RRC connection is re-established, the security algorithm configuration cell may be added to the RRC connection re-establishment message sent by the eNB to the UE. The method to solve. However, at the same time, a new problem has been introduced: The new security algorithm configuration can only be sent to the UE through the RRC connection re-establishment message, and the RRC connection re-establishment message itself is not integrity-protected, therefore, if the malicious attacker will The data encryption algorithm carried in the RRC connection re-establishment message is falsified, and the eNB and the UE cannot be discovered in time. As a result, there are a large number of invalid data packets that the eNB cannot decrypt in the air interface for a period of time, thus not only wasting air interface resources. And further seriously affect the user experience. Summary of the invention

In view of the above, the main purpose of the present invention is to provide a method and system for implementing synchronization of an access layer security algorithm, which can protect a user plane encryption algorithm in an RRC connection re-establishment from being tampered with, and avoid an AS security algorithm exception, to the greatest extent. It avoids the waste of bandwidth caused by invalid data packets, improves the timeliness of abnormal recovery, and improves the user experience before and after switching.

In order to achieve the above object, the technical solution of the present invention is achieved as follows:

A method for implementing protection of an access layer security algorithm includes:

In the radio resource control (RRC) connection re-establishment process, the evolved Node B (eNB) notifies the user equipment (UE) whether to update the access stratum (AS) security algorithm;

The UE encrypts the completion of the RRC connection reestablishment by using the corresponding AS security algorithm according to the notification. And integrity protection;

The eNB uses the locally configured AS security algorithm to decrypt and complete the integrity of the RRC connection reestablishment, and determines whether to initiate the security acknowledgment based on the currently used AS security calculation.

In the RRC connection re-establishment process, the eNB notifies the UE whether to update the AS security algorithm, specifically:

After receiving the RRC connection re-establishment request from the UE, the eNB selects an AS security algorithm, and carries an AS security algorithm configuration information element in the RRC connection re-establishment message sent to the UE;

The AS security algorithm configures whether a cell presence flag is used to notify the UE whether the eNB's own AS security algorithm is updated.

If the AS security algorithm configuration cell presence flag is displayed as being present, the method further includes:

The eNB carries an algorithm configuration cell for carrying the updated AS security algorithm parameter in the RRC connection re-establishment message.

The eNB selecting an AS security algorithm includes:

The eNB determines, according to the configuration of the original AS security algorithm carried in the handover request message obtained before the RRC connection re-establishment process, whether the AS security algorithm configured by the eNB supports the original AS security algorithm, and if not, the eNB is configured according to the eNB. The AS security algorithm configured by the AS and the security capability of the UE carried in the handover request message, select a AS security algorithm with the highest priority and supported by the UE as the selected new AS security algorithm, and select the AS security algorithm. Save to local, configure locally with the new AS security algorithm configuration;

If the eNB supports the configuration of the original AS security algorithm carried in the handover request message, the original AS security algorithm is the selected AS security algorithm, and the local AS security algorithm configuration is used for local configuration.

The UE enters the completion of the RRC connection reestablishment by using the corresponding AS security algorithm according to the notification Line encryption and integrity protection, including:

After receiving the RRC connection re-establishment message from the eNB, the UE determines whether the AS security algorithm needs to be updated according to whether the AS security algorithm is configured in the AS security algorithm, and if the AS security algorithm configuration cell exists, the flag is displayed as If yes, the algorithm in the RRC connection re-establishment message is enabled to configure the updated AS security algorithm carried by the cell for local configuration; after that, the UE uses the updated AS security algorithm to encrypt and complete the RRC connection re-establishment message. After being protected, it is sent to the eNB;

If the AS security algorithm configuration cell indicates that the presence flag does not exist, the original AS security algorithm is still used for local configuration. After that, the UE uses the original AS security algorithm to encrypt and integrity protect the RRC connection re-establishment message. eNB.

The eNB determines whether to initiate the security confirmation according to the currently used AS security calculation, which specifically includes:

If the eNB's locally configured AS security algorithm is an updated AS security algorithm, the eNB initiates a security acknowledgment, and sends a security mode command SMC message to the UE for performing integrity protection using the updated AS security algorithm; After receiving the SMC message, the UE performs the SMC corresponding processing, and sends a security mode complete message to the eNB;

If the eNB's locally configured AS security algorithm is not updated, then the eNB does not need to initiate a security acknowledgment.

A system for implementing protection of an access layer security algorithm, comprising an eNB and a UE, where the eNB is configured to notify the UE whether to update the AS security algorithm during the RRC connection re-establishment process; and use the locally configured AS security algorithm to the RRC The completion of the connection re-establishment is performed for decryption and integrity verification, and whether the security confirmation is initiated according to the currently used AS security calculation;

The UE is configured to perform encryption and integrity protection on the completion of the RRC connection reestablishment by using the corresponding AS security algorithm according to the notification.

It can be seen from the technical solution provided by the present invention that the present invention is on the target side of the handover failure. In the initiated RRC re-establishment process, if the base station side needs to perform the AS security algorithm update, the RRC connection reestablishment message carries the updated AS security algorithm, and immediately initiates the SMC process for security confirmation after the re-establishment is completed. The invention protects the user plane encryption algorithm in the RRC link re-establishment from being tampered with, avoids the AS security algorithm exception, minimizes waste of bandwidth of the invalid data packet, improves the timeliness of abnormal recovery, and further Improved user experience before and after switching. DRAWINGS

1 is a schematic flowchart of a process in which an AS security algorithm is out of synchronization during an RRC connection re-establishment process in the prior art;

2 is a schematic diagram of a process for implementing synchronization of an AS algorithm when RRC connection reestablishment occurs after handover in the present invention;

3 is a schematic structural diagram of a system for implementing synchronization of an AS security algorithm according to the present invention; FIG. 4 is a schematic flowchart of a first embodiment of synchronizing AS algorithms according to the present invention; Schematic diagram of the process. detailed description

FIG. 2 is a schematic diagram of a process for implementing synchronization of an AS algorithm when an RRC connection reestablishment occurs after handover, and as shown in FIG. 2, the following steps are included:

Step 200: In the RRC connection re-establishment process, the eNB notifies the UE whether to update the AS security algorithm.

In this step, after receiving the RRC connection re-establishment request from the UE, the eNB selects an AS security algorithm, and carries an AS security algorithm configuration cell presence flag in the RRC connection re-establishment message sent to the UE, to notify the UE, Whether the eNB's own AS security algorithm is updated. If the AS security algorithm configuration cell presence flag is displayed as being present, the eNB also carries an algorithm configuration cell in the RRC connection re-establishment message, which is used to carry the updated AS security algorithm parameter (package) Integrity protection algorithm and encryption algorithm).

The eNB selects an AS security algorithm including:

The eNB determines, according to the configuration of the original AS security algorithm carried in the handover request message, whether the AS security algorithm configured by the eNB supports the original AS security algorithm (including the integrity protection algorithm and the encryption algorithm), if not supported (integrity protection algorithm and encryption algorithm) If there is an unsupported one, it is considered that the original AS security algorithm is not supported. The eNB selects the AS security algorithm with the highest priority and the UE support according to the AS security algorithm configured by the AS and the UE security capability carried in the handover request message. (including the integrity protection algorithm and the encryption algorithm) as the selected new AS security algorithm (that is, satisfying the algorithm replacement condition), and save the selected AS security algorithm to the local, and use the new AS security algorithm configuration for local configuration;

If the eNB supports the configuration of the original AS security algorithm carried in the handover request message, the original AS security algorithm is the selected AS security algorithm, and the local configuration is configured using the original AS security algorithm configuration.

It should be noted that if the algorithm replacement condition is not met, the eNB performs local configuration using the original AS security algorithm configuration.

Step 201: The UE performs encryption and integrity protection on the completion of the RRC connection reestablishment by using the corresponding AS security algorithm according to the notification.

In this step, after receiving the RRC connection re-establishment message from the eNB, the UE determines whether the AS security algorithm needs to be updated according to whether the AS security algorithm is configured in the AS security algorithm, if the AS security algorithm configures the cell to exist. If it is displayed as being present, the algorithm in the RRC connection re-establishment message is enabled to configure the updated AS security algorithm carried by the cell for local configuration; after that, the UE uses the updated AS security algorithm to encrypt the RRC connection re-establishment completion message. The integrity is protected and sent to the eNB.

If the AS security algorithm configuration cell indicates that the presence flag does not exist, the original AS security algorithm is still used for local configuration. After that, the UE uses the original AS security algorithm to re-establish the RRC connection. The message is sent to the eNB after encryption and integrity protection.

Step 202: The eNB uses the locally configured AS security algorithm to perform decryption and integrity verification on the completion of the RRC connection reestablishment, and determines whether to initiate the security confirmation according to the currently used AS security calculation.

In this step, if the eNB uses the locally configured AS security algorithm to decrypt and complete the integrity message of the received RRC connection reestablishment.

If the eNB's locally configured AS security algorithm is an updated AS security algorithm, the eNB initiates a security acknowledgment, and sends a security mode command (SMC, Security Mode Command) message to the UE using the updated AS security algorithm for integrity protection; After receiving the SMC message, the UE performs the SMC corresponding processing, and sends a Security Mode Complete message to the eNB. If the eNB locally configured AS security algorithm is not updated, the eNB does not need to initiate the security confirmation.

In the RRC re-establishment process initiated by the target side of the handover failure, if the base station side needs to perform the AS security algorithm update, the RRC connection reestablishment message carries the updated AN security algorithm, and is initiated immediately after the re-establishment is completed. The SMC process performs a security check. The invention protects the user plane encryption algorithm in the RRC link re-establishment from being tampered with, avoids the AS security algorithm exception, minimizes waste of bandwidth of the invalid data packet, improves the timeliness of abnormal recovery, and further Improved user experience before and after switching.

A system is provided for the method of the present invention. FIG. 3 is a schematic structural diagram of a system for implementing synchronization of an AS security algorithm according to the present invention. As shown in FIG. 3, an eNB and a UE are included, where

The eNB is configured to notify the UE whether to update the AS security algorithm during the RRC connection re-establishment process, and perform decryption and integrity verification on the completion of the RRC connection reestablishment by using the locally configured AS security algorithm, and according to the currently used AS security Calculate whether to initiate a security confirmation;

The UE is configured to perform encryption and integrity protection on the completion of the RRC connection reestablishment by using the corresponding AS security algorithm according to the notification. 4 is a schematic flowchart of the first embodiment of the AS algorithm synchronization. In the first embodiment, after the eNB receives the RRC connection re-establishment request, it determines that the AS security algorithm does not need to be updated, as shown in FIG. The following steps:

Step 400: The UE sends an RRC connection re-establishment request message to the eNB.

Step 401 to step 402: After receiving the RRC connection re-establishment request message, the eNB determines that the AS security algorithm is not required to be updated, and configures the local AS security algorithm parameter locally.

In this step, the eNB determines that the AS security algorithm configured by the eNB supports the original AS security algorithm (including the integrity protection algorithm and the encryption algorithm) according to the configuration of the original AS security algorithm carried in the handover request message, and the eNB does not need to update the AS security algorithm. The eNB uses the original AS security algorithm parameters to configure the local. The eNB user plane configuration does not include the AS security algorithm parameters, that is, the original AS security algorithm is still used for configuration.

Step 403: Set the AS security algorithm configuration cell presence flag to be absent, and carry it in the RRC connection re-establishment message, and send the RRC connection re-establishment message to the UE.

Step 404: After receiving the RRC connection re-establishment message, the UE configures whether the cell existence flag is absent according to the AS security algorithm, that is, the AS security algorithm is not updated, and determines that the AS security algorithm does not need to be updated.

Step 405 to step 406: After the UE uses the original AS security algorithm to perform encryption and integrity protection on the RRC connection re-establishment complete message, the UE sends the message to the eNB. The eNB uses the original AS security algorithm to perform the received RRC connection re-establishment completion message. Decryption and integrity check.

Step 407: The eNB determines that the SMC process does not need to be initiated.

FIG. 5 is a schematic flowchart of the second embodiment of the AS algorithm synchronization. In the second embodiment, after the eNB receives the RRC connection re-establishment request, the eNB determines that the AS security algorithm needs to be updated, as shown in FIG. The following steps:

Step 500: The UE sends an RRC connection re-establishment request message to the eNB.

Step 501 to step 503: After receiving the RRC connection re-establishment request message, the eNB determines that the request is needed. To update the AS security algorithm, reselect the AS security algorithm and configure the local with the new AS security algorithm.

In this step, the eNB determines, according to the original AS security algorithm configuration carried in the handover request message, that the AS security algorithm configured by the eNB does not support the original AS security algorithm (including the integrity protection algorithm and the encryption algorithm), and the eNB configures according to the configuration. The AS security algorithm carried in the AS security algorithm and the handover request message selects a AS security algorithm (including an integrity protection algorithm and an encryption algorithm) with the highest priority and supported by the UE as the selected new AS security algorithm (that is, the algorithm replacement is satisfied). Conditionally, the selected AS security algorithm is saved locally, and is configured locally by using the new AS security algorithm configuration, where the newly selected AS security algorithm parameters are carried when configured for the eNB user plane.

Step 504: Set the AS security algorithm configuration cell presence flag to exist, and carry it in the RRC connection re-establishment message together with the algorithm configuration cell carrying the selected new AS security algorithm, and re-establish the RRC connection. The message is sent to the UE.

Step 505: After receiving the RRC connection re-establishment message, the UE configures the presence or absence of the cell according to the AS security algorithm carried in the UE, and configures the local security algorithm information of the algorithm configuration cell in the RRC connection re-establishment message to configure the local , and enable the new AS security algorithm carried in the message.

Step 506 to step 507: After the UE uses the original AS security algorithm to perform encryption and integrity protection on the RRC connection re-establishment complete message, the UE sends the message to the eNB. The eNB uses the original AS security algorithm to perform the received RRC connection re-establishment completion message. Decryption and integrity check.

Step 508: Since the eNB updates the AS security algorithm, it is determined that the SMC process needs to be initiated.

Step 509: The eNB carries the current AS security algorithm information in the SMC message, and sends the SMC message to the UE.

Step 510: After receiving the SMC message, the UE performs corresponding processing on the SMC, and the specific step is performed. The implementation belongs to the prior art and will not be described here.

Step 511: The UE sends a security mode complete message to the eNB, and the AS security algorithm is synchronized. The above description is only for the preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included. Within the scope of protection of the present invention.

Claims

Claim

A method for implementing protection of an access layer security algorithm, comprising: in a radio resource control (RRC) connection re-establishment process, an evolved Node B (eNB) notifying a user equipment (UE) whether to update an access layer (AS) security algorithm;

The UE performs encryption and integrity protection on the completion of the RRC connection reestablishment by using the corresponding AS security algorithm according to the notification;

The method according to claim 1, wherein, in the RRC connection reestablishment process, the eNB notifies the UE whether to update the AS security algorithm, specifically:

The method according to claim 2, wherein if the AS security algorithm configuration cell presence flag is displayed as being present, the method further includes:

The method according to claim 2 or 3, wherein the selecting an AS security algorithm by the eNB comprises:

The eNB determines, according to the configuration of the original AS security algorithm carried in the handover request message obtained before the RRC connection re-establishment process, whether the AS security algorithm configured by the eNB supports the original AS security algorithm, and if not, the eNB is configured according to the eNB. The AS security algorithm configured by itself and the UE security capability carried in the handover request message, and selecting a highest priority and supported by the UE The AS security algorithm is selected as the new AS security algorithm, and the selected AS security algorithm is saved locally, and configured locally by using the new AS security algorithm configuration.

The method according to claim 3, wherein the UE performs encryption and integrity protection on the completion of the RRC connection reestablishment by using the corresponding AS security algorithm according to the notification, which specifically includes:

The method according to claim 2 or 3, wherein the eNB determines whether to initiate the security confirmation according to the current AS security calculation, which specifically includes:

A system for implementing protection of an access layer security algorithm, comprising: an eNB and a UE, where

The eNB is configured to notify the UE whether to update the AS security algorithm during the RRC connection re-establishment process, and is further configured to perform decryption and integrity verification on the completion of the RRC connection reestablishment by using the locally configured AS security algorithm, and according to the current application. AS security calculation determines whether to initiate a security confirmation;