Key deduction method and apparatus

Abstract

A key deduction method and apparatus, and relating to the field of communications. In the method, an access and mobility management network element receiving a first registration request message from a terminal device, the first registration request message being used for requesting, for the terminal device, registration to a network by means of a first 3GPP access, generating a first key, and sending the first key to a first access network device, the first key being a key used for communication between the terminal device and the first access network device. The access and mobility management network element also receiving a second registration request message from the terminal device, the second registration request message being used for requesting, for the terminal device, registration to the network by means of a second 3GPP access, generating a second key, the second key being a key used for communication between the terminal device and a second access network device, and sending the second key to the second access network device, the first key being different from the second key. By using the described method, two different keys are generated for two 3GPP accesses, and key isolation can be realized.

Description

A key deduction method and device

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office of the People's Republic of China on September 26, 2023, with application number 202311260044.3 and invention name "A Key Derivation Method and Device", the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The present application relates to the field of communication technology, and in particular to a key derivation method and device. Background Art

[0004] Currently, terminal devices can register in the same access and mobility management function (AMF) network element through 3rd generation partnership project (3GPP) access and non-3GPP access, and then connect to the same public land mobile network (PLMN).

[0005] Specifically, when a terminal device is connected to the same PLMN through 3GPP access and non-3GPP access, the terminal device can perform only one primary authentication with the AMF network element to maintain a common security context. For 3GPP access, the terminal device registers with the AMF through the next generation NodeB (gNB) in the 5G mobile communication system. For non-3GPP access, the terminal device also registers with the AMF through the non-3GPP InterWorking Function (N3IWF) network element. Therefore, the AMF maintains the parameters of the NAS connection for 3GPP access and non-3GPP access respectively, thereby achieving secure isolation of the two accesses.

[0006] However, when a terminal device connects to the same PLMN via two 3GPP access points, there is no corresponding key derivation solution.

[0007] Summary of the Invention

[0008] The present application provides a key derivation method and apparatus to solve the problem of how to derive a key when a terminal device is connected to the same PLMN through two 3GPP access points.

[0009] In a first aspect, the present application provides a key derivation method, which can be executed by an access and mobility management network element or a module (such as a chip) in the access and mobility management network element. The method includes: receiving a first registration request message from a terminal device, the first registration request message is used to request the terminal device to register to a network through a first Third Generation Partnership Project 3GPP access; generating a first key, the first key is a key used for communication between the terminal device and the first access network device; the first access network device is used for the first 3GPP access; sending the first key to the first access network device; receiving a second registration request message from the terminal device, the second registration request message is used to request the terminal device to register to a network through a second 3GPP access; generating a second key, the second key is a key used for communication between the terminal device and the second access network device, the second access network device is used for the second 3GPP access; the first key is different from the second key; and sending the second key to the second access network device. Using the above method, when a terminal device registers in the same access and mobility management network element through two 3GPP accesses, the access and mobility management network element generates two different keys for the two 3GPP accesses, that is, the key used for communication between the terminal device and the first access network device is different from the key used for communication between the terminal device and the second access network device, which can achieve key isolation and ensure communication security.

[0010] In one possible design, the first registration request message and / or the second registration request message includes indication information, where the indication information is used to indicate that the terminal device is connected to the network via two 3GPP accesses.

[0011] With the above design, the access and mobility management network element can determine, through the indication information, that the terminal device is connected to the network via two 3GPP accesses. The two 3GPP accesses can also be replaced by multiple 3GPP accesses.

[0012] In one possible design, when generating a first key, the first key is generated according to a first access type identifier corresponding to the first 3GPP access; when generating a second key, the second key is generated according to a second access type identifier corresponding to the second 3GPP access, and the first access type identifier and the second access type identifier are different.

[0013] With the above design, by using different access type identifiers in the two 3GPP access processes, it is possible to ensure that the first key and the second key are different, thereby achieving key isolation.

[0014] In one possible design, the second registration request message includes the indication information; before generating the second key, the second access type identifier is determined for the second 3GPP access based on the indication information.

[0015] With the above design, the access and mobility management network element can determine through indication information that the terminal device is connected to the network via two 3GPP accesses, and then determine a second access type identifier for the second 3GPP access that is different from the first access type identifier.

[0016] In one possible design, the first registration request message includes the indication information; before generating the first key, the first access type identifier is determined for the first 3GPP access according to the indication information, and the first access type identifier is one of the dual 3GPP access type identifiers; before generating the second key, the second access type identifier is determined for the second 3GPP access, and the second access type identifier is the other of the dual 3GPP access type identifiers.

[0017] With the above design, the access and mobility management network element can determine through indication information that the terminal device is connected to the network through two 3GPP accesses, and then use one of the dual 3GPP access type identifiers as the first access type identifier, and use the other of the dual 3GPP access type identifiers as the second access type identifier, so that the first access type identifier is different from the second access type identifier.

[0018] In one possible design, the second access type identifier is an unused one of the dual 3GPP access type identifiers.

[0019] In one possible design, a first registration acceptance message is sent to the terminal device, the first registration acceptance message including the first access type identifier; and / or a second registration acceptance message is sent to the terminal device, the second registration acceptance message including the second access type identifier.

[0020] With the above design, the terminal device can obtain the first access type identifier through the first registration acceptance message, and obtain the second access type identifier through the second registration acceptance message.

[0021] In one possible design, the first bearer parameter includes the first access type identifier, and the second bearer parameter includes the second access type identifier; the first NAS signaling is securely protected using the NAS security protection key and the first bearer parameter, and the first NAS signaling corresponds to the first 3GPP access; the second NAS signaling is securely protected using the NAS security protection key and the second bearer parameter, and the second NAS signaling corresponds to the second 3GPP access.

[0022] In the above manner, by using different bearer parameters, the problem of key stream reuse caused by two 3GPPs using the same NAS security protection key can be avoided.

[0023] In one possible design, when generating a first key, the first key is generated based on a third access type identifier and an identifier of the first 3GPP access, and the third access type identifier indicates that the access type is 3GPP access; when generating a second key, the second key is generated based on the third access type identifier and an identifier of the second 3GPP access; the identifier of the first 3GPP access is different from the identifier of the second 3GPP access.

[0024] By adopting the above method, by providing new identifiers for different 3GPP accesses during two 3GPP access processes, it is possible to ensure that the first key is different from the second key, thereby achieving key isolation.

[0025] In one possible design, the first registration request message includes the indication information; before generating the first key, the identifier of the first 3GPP access is determined for the first 3GPP access according to the indication information; before generating the second key, the identifier of the second 3GPP access is determined for the second 3GPP access.

[0026] With the above design, the access and mobility management network element can determine through indication information that the terminal device is connected to the network through two 3GPP accesses, and then determine the identifier of the first 3GPP access for the first 3GPP access, and determine the identifier of the second 3GPP access for the second 3GPP access.

[0027] In one possible design, when determining the identifier of the first 3GPP access for the first 3GPP access based on the indication information, two 3GPP access identifiers are obtained from the data management network element based on the indication information; one of the two 3GPP identifiers is used as the identifier of the first 3GPP access; and when determining the identifier of the second 3GPP access for the second 3GPP access, the other of the two 3GPP identifiers is used as the identifier of the second 3GPP access.

[0028] By adopting the above method, the access and mobility management network element can obtain two pre-configured 3GPP access identifiers from the data management network element according to the indication information, and use the two 3GPP access identifiers as the first 3GPP access identifier and the second 3GPP access identifier respectively.

[0029] In one possible design, a first registration acceptance message is sent to the terminal device, wherein the first registration acceptance message includes an identifier of the first 3GPP access; and a second registration acceptance message is sent to the terminal device, wherein the second registration acceptance message includes an identifier of the second 3GPP access.

[0030] With the above design, the terminal device can obtain the identifier of the first 3GPP access through the first registration accept message, and obtain the identifier of the second 3GPP access through the second registration accept message.

[0031] In one possible design, the first registration request message includes an identifier of the first 3GPP access, and the second registration request message includes an identifier of the second 3GPP access.

[0032] With the above design, the terminal device can provide the identifier of the first 3GPP access and the identifier of the second 3GPP access.

[0033] In one possible design, a first bearer parameter corresponds to an identifier of the first 3GPP access, and a second bearer parameter corresponds to an identifier of the second 3GPP access; the NAS security protection key and the first bearer parameter are used to securely protect the first NAS signaling, and the first NAS signaling corresponds to the first 3GPP access; the NAS security protection key and the second bearer parameter are used to securely protect the second NAS signaling, and the second NAS signaling corresponds to the second 3GPP access.

[0034] With the above design, by using different bearer parameters, the problem of key stream reuse caused by two 3GPPs using the same NAS security protection key can be avoided.

[0035] In one possible design, when generating a first key, the first key is generated according to a first value of an uplink NAS counter; when generating a second key, the second key is generated according to a second value of the uplink NAS counter; wherein the first 3GPP access and the second 3GPP access share the uplink NAS counter, and the first value is different from the second value.

[0036] With the above design, by using different values ​​of the same uplink NAS counter in two 3GPP access processes, it is possible to ensure that the first key and the second key are different, thereby achieving key isolation.

[0037] In a second aspect, the present application provides a key derivation method, which can be executed by a terminal device or a module (such as a chip) in the terminal device. The method includes: sending a first registration request message to an access and mobility management network element, the first registration request message is used to request the terminal device to register with the network through a first 3GPP access; generating a first key, the first key is a key used for communication between the terminal device and the first access network device; the first access network device is used for the first 3GPP access; sending a second registration request message to the access and mobility management network element, the second registration request message is used to request the terminal device to register with the network through a second 3GPP access; generating a second key, the second key is a key used for communication between the terminal device and the second access network device, the second access network device is used for the second 3GPP access; the first key is different from the second key.

[0038] Using the above method, when the terminal device registers in the same access and mobility management network element through two 3GPP accesses, the terminal device generates two different keys for the two 3GPP accesses, that is, the key used for communication between the terminal device and the first access network device is different from the key used for communication between the terminal device and the second access network device, which can achieve key isolation and ensure communication security.

[0039] In one possible design, the first registration request message and / or the second registration request message includes indication information, where the indication information is used to indicate that the terminal device is connected to the network via two 3GPP accesses.

[0040] With the above design, the terminal device can notify the access and mobility management network element through the indication information that the terminal device is connected to the network through two 3GPP accesses. The two 3GPP accesses can also be replaced by multiple 3GPP accesses.

[0041] In one possible design, when generating a first key, the first key is generated according to a first access type identifier corresponding to the first 3GPP access; when generating a second key, the second key is generated according to a second access type identifier corresponding to the second 3GPP access, and the first access type identifier and the second access type identifier are different.

[0042] With the above design, by using different access type identifiers in the two 3GPP access processes, it is possible to ensure that the first key and the second key are different, thereby achieving key isolation.

[0043] In one possible design, before generating the first key, the first access type identifier is determined for the first 3GPP access, and the first access type identifier is one of the dual 3GPP access type identifiers; before generating the second key, the second access type identifier is determined for the second 3GPP access, and the second access type identifier is the other of the dual 3GPP access type identifiers.

[0044] In one possible design, the second access type identifier is an unused one of the dual 3GPP access type identifiers.

[0045] In one possible design, a first registration acceptance message is received from the access and mobility management network element, and the first registration acceptance message includes the first access type identifier; and / or a second registration acceptance message is received from the access and mobility management network element, and the first registration acceptance message includes the second access type identifier.

[0046] With the above design, the terminal device can obtain the first access type identifier through the first registration acceptance message, and / or obtain the second access type identifier through the second registration acceptance message, that is, the terminal device obtains the first access type identifier and / or the second access type identifier from the access and mobility management network element.

[0047] In one possible design, a first AS security mode command is received from the first access network device, the first AS security mode command including the first access type identifier; and / or a second AS security mode command is received from the second access network device, the second AS security mode command including the second access type identifier.

[0048] With the above design, the terminal device can obtain the first access type identifier through the first AS security mode command, and / or obtain the second access type identifier through the second AS security mode command, that is, the terminal device obtains the first access type identifier from the first access network device, and / or obtains the second access type identifier from the second access network device.

[0049] In one possible design, the first bearer parameter includes the first access type identifier, and the second bearer parameter includes the second access type identifier; the first NAS signaling is securely protected using the NAS security protection key and the first bearer parameter, and the first NAS signaling corresponds to the first 3GPP access; the second NAS signaling is securely protected using the NAS security protection key and the second bearer parameter, and the second NAS signaling corresponds to the second 3GPP access.

[0050] In the above manner, by using different bearer parameters, the problem of key stream reuse caused by two 3GPPs using the same NAS security protection key can be avoided.

[0051] In one possible design, when generating a first key, the first key is generated based on a third access type identifier and an identifier of the first 3GPP access, and the third access type identifier indicates that the access type is 3GPP access; when generating a second key, the second key is generated based on the third access type identifier and an identifier of the second 3GPP access; the identifier of the first 3GPP access is different from the identifier of the second 3GPP access.

[0052] By adopting the above method, by providing new identifiers for different 3GPP accesses during two 3GPP access processes, it is possible to ensure that the first key is different from the second key, thereby achieving key isolation.

[0053] In one possible design, before generating the first key, an identifier of the first 3GPP access is determined for the first 3GPP access; before generating the second key, an identifier of the second 3GPP access is determined for the second 3GPP access.

[0054] In one possible design, a first registration acceptance message is received from the access and mobility management network element, wherein the first registration acceptance message includes an identifier of the first 3GPP access; and / or a second registration acceptance message is received and sent from the access and mobility management network element, wherein the second registration acceptance message includes an identifier of the second 3GPP access.

[0055] With the above design, the terminal device can obtain the identifier of the first 3GPP access through the first registration acceptance message, and / or obtain the identifier of the second 3GPP access through the second registration acceptance message, that is, the terminal device can obtain the identifier of the first 3GPP access and / or the identifier of the second 3GPP access from the access and mobility management network element.

[0056] In one possible design, a first AS security mode command is received from the first access network device, wherein the first AS security mode command includes an identifier of the first 3GPP access; and / or a second AS security mode command is received from the second access network device, wherein the second AS security mode command includes an identifier of the second 3GPP access.

[0057] With the above design, the terminal device can obtain the identifier of the first 3GPP access through the first AS security mode command, and / or obtain the identifier of the second 3GPP access through the second AS security mode command, that is, the terminal device obtains the identifier of the second 3GPP access from the first access network device, and / or obtains the identifier of the second 3GPP access from the second access network device.

[0058] In one possible design, the first registration request message includes an identifier of the first 3GPP access, and the second registration request message includes an identifier of the second 3GPP access.

[0059] With the above design, the terminal device can provide the identifier of the first 3GPP access and the identifier of the second 3GPP access.

[0060] In one possible design, a first bearer parameter corresponds to an identifier of the first 3GPP access, and a second bearer parameter corresponds to an identifier of the second 3GPP access; a first NAS signaling is securely protected using a NAS security protection key and the first bearer parameter, and the first NAS signaling corresponds to the first 3GPP access; and a second NAS signaling is securely protected using the NAS security protection key and the second bearer parameter, and the second NAS signaling corresponds to the second 3GPP access.

[0061] In one possible design, when generating a first key, the first key is generated according to a first value of an uplink NAS counter; when generating a second key, the second key is generated according to a second value of the uplink NAS counter; wherein the first 3GPP access and the second 3GPP access share the uplink NAS counter, and the first value is different from the second value.

[0062] With the above design, by using different values ​​of the same uplink NAS counter in two 3GPP access processes, it is possible to ensure that the first key and the second key are different, thereby achieving key isolation.

[0063] In a third aspect, the present application provides a communication device, which includes a unit for executing any one of the methods described in any one of the above aspects.

[0064] In a fourth aspect, the present application provides a communication device comprising at least one processing element and at least one storage element, wherein the at least one storage element is used to store programs and data, and the at least one processing element is used to read and execute the programs and data stored in the storage element, so that the method described in any one of the above aspects of the present application is implemented.

[0065] In a fifth aspect, the present application further provides a computer program, which, when executed on a computer, enables the computer to execute any of the methods described in any of the above aspects.

[0066] In a sixth aspect, the present application provides a communication device, comprising: an interface circuit; the interface circuit is used to provide input and / or output of programs or instructions to at least one processor; the at least one processor is used to execute the program or instructions so that the communication device can implement any of the methods described in any of the above aspects.

[0067] In one possible manner, the communication device includes the at least one processor.

[0068] In one possible manner, the communication device includes the at least one memory.

[0069] In a seventh aspect, the present application provides a computer storage medium storing a software program. When the software program is read and executed by one or more processors, it can implement any of the methods described in any of the above aspects.

[0070] In an eighth aspect, the present application provides a computer program product comprising instructions, which, when executed on a computer, enables the computer to execute any of the methods described in any of the above aspects.

[0071] In a ninth aspect, a chip system is provided, comprising at least one chip and a memory, wherein the at least one chip is used to read and execute a program stored in the memory to implement any of the methods described in any one of the above aspects.

[0072] In a tenth aspect, a communication system is provided, comprising a terminal device, a first access network device, a second access network device, and an access and mobility management network element. The terminal device is configured to perform any of the methods described in the first aspect, and the access and mobility management network element is configured to perform any of the methods described in the second aspect.

[0073] Based on the implementations provided in the above aspects, this application can also be further combined to provide more implementations. BRIEF DESCRIPTION OF THE DRAWINGS

[0074] FIG1 is a schematic diagram of the architecture of a mobile communication system used in an embodiment of the present application;

[0075] FIG2 is a schematic diagram of the key derivation architecture in the 5G system of this application;

[0076] FIG3A is a schematic diagram of using a confidentiality key to protect a message in this application;

[0077] FIG3B is a schematic diagram of using an integrity protection key to protect a message in this application;

[0078] FIG4 is a schematic diagram of a terminal device connected to the same PLMN via two 3GPP access points in this application;

[0079] FIG5 is one of the flow charts summarizing a key derivation method in this application;

[0080] FIG6 is a second flowchart of a key derivation method in this application;

[0081] FIG7 is a third flowchart of a key derivation method in this application;

[0082] FIG8 is a fourth flow chart of an overview of a key derivation method in this application;

[0083] FIG9 is a schematic structural diagram of a communication device in this application;

[0084] FIG10 is a schematic structural diagram of another communication device in this application. DETAILED DESCRIPTION

[0085] The embodiments of the present application can be applied to various communication systems, such as: global system for mobile communications (GSM) system, code division multiple access (CDMA) system, wideband code division multiple access (WCDMA) system, general packet radio service (GPRS), long term evolution (LTE) system, LTE frequency division duplex (FDD) system, LTE time division duplex (TDD), universal mobile telecommunication system (UMTS), world-wide interoperability for microwave access (WIMAX) communication system, fifth generation (5G) system or new radio (NR), or applied to future communication systems or other similar communication systems.

[0086] Figure 1 shows the architecture of the 5G communication system, as standardized by the 3rd Generation Partnership Project (3GPP). The 5G network architecture shown in Figure 1 includes terminal devices, access network devices, and core network devices. Terminal devices access the data network (DN) through the access network and core network devices.

[0087] The access network device may be a radio access network (RAN) device. For example: a base station, an evolved NodeB (eNodeB), a transmission reception point (TRP), a next generation NodeB (gNB) in a 5G mobile communication system, a next generation base station in a sixth generation (6G) mobile communication system, a base station in a future mobile communication system, or an access node in a wireless fidelity (WiFi) system, etc.; it may also be a module or unit that performs part of the functions of a base station, for example, a centralized unit (CU) or a distributed unit (DU). The radio access network device may be a macro base station, a micro base station or an indoor station, a relay node or a donor node, etc. The embodiments of the present application do not limit the specific technology and specific device form adopted by the radio access network device.

[0088] Terminal devices can be user equipment (UE), mobile stations, mobile terminals, etc. Terminal devices can be widely used in various scenarios, such as device-to-device (D2D), vehicle-to-everything (V2X) communication, machine-type communication (MTC), the Internet of Things (IoT), virtual reality, augmented reality, industrial control, autonomous driving, telemedicine, smart grids, smart furniture, smart offices, smart wearables, smart transportation, and smart cities. Terminal devices can be mobile phones, tablets, computers with wireless transceiver capabilities, wearable devices, vehicles, urban air vehicles (such as drones and helicopters), ships, robots, robotic arms, smart home devices, etc.

[0089] Access network equipment and terminal devices can be fixed or mobile. They can be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; on water; or in the air on aircraft, balloons, and satellites. The embodiments of this application do not limit the application scenarios of access network equipment and terminal devices.

[0090] Among them, the core network equipment includes user plane function (UPF) network element, AMF network element, session management function (SMF), network exposure function (NEF) network element, network function repository function (NRF) network element, unified data management (UDM) network element, policy control function (PCF) network element, application function (AF) network element, authentication server function (AUSF) network element, network slice selection function (NSSF) network element, etc. Among them, the UPF network element is the user plane network element, and the other network elements mentioned above are control plane network elements.

[0091] The interface between each control plane network element can be a service-oriented interface (as shown in Figure 1) or a point-to-point interface. This application does not limit this and only uses Figure 1 as an example for explanation.

[0092] The following is a brief introduction to some core network equipment:

[0093] 1. The SMF network element (SMF) is primarily used for session management, terminal device IP address allocation and management, selection of endpoints for manageable user equipment plane functions, policy control, or charging function interfaces, and downlink data notification. Nsmf is a service-based interface provided by SMF, through which SMF can communicate with other network functions.

[0094] 2. AMF network element, referred to as AMF, is mainly used for mobility management and access management. NMF is a service-based interface provided by AMF. AMF can communicate with other network functions through NMF.

[0095] 3. The UDM network element, or UDM for short, handles user identification, subscription, access authentication, registration, or mobility management. Nudm is the service-based interface provided by the UDM, through which the UDM can communicate with other network functions.

[0096] 4. UPF network element, referred to as UPF, is used for packet routing and forwarding, or quality of service (QoS) processing of user plane data.

[0097] 5. AUSF network element, referred to as AUSF, is mainly used for user authentication, etc. Nausf is a service-based interface provided by AUSF, through which AUSF can communicate with other network functions.

[0098] It is understandable that the core network device may also include other network elements, which is not limited in this application. The above network elements are examples of one implementation method, and this application does not exclude the existence of network elements or devices with the above network element functions in 6G or newer wireless communication systems with other names or other forms. The above network elements or functions can be network elements in hardware devices, software functions running on dedicated hardware, or virtualized functions instantiated on a platform (for example, a cloud platform). As a possible implementation method, the above network elements or functions can be implemented by one device, or by multiple devices together, or as a functional module within a device, and this embodiment of the application does not specifically limit this.

[0099] FIG2 shows an exemplary key derivation architecture in a 5G system.

[0100] Authentication can be performed between the terminal device and the service network. Specifically, two authentication methods can be used: Extensible Authentication Protocol Authentication and Key Agreement (EAP-AKA′) and 5G AKA.

[0101] The terminal device stores a long-term key K and related functions. During bidirectional authentication, the terminal device can use the long-term key K and related functions to verify the authenticity of the network. The long-term key K can be stored in the universal subscriber identity module (USIM) of the terminal device. Correspondingly, the network side also stores the long-term key K and related functions. For example, the long-term key K and related functions can be stored in a UDM or an authentication repository and processing function (ARPF) network element (ARPF for short).

[0102] On the serving network side, the UDM or ARPF derives the cipher key (CK) and integrity key (IK) from the long-term key K. If the 5G AKA authentication method is used, the UDM or ARPF can derive KAUSF from CK and IK. If the EAP-AKA' authentication method is used, the UDM or ARPF derives CK' and IK' from CK and IK and sends CK' and IK' to the AUSF. The AUSF further derives KAUSF from CK' and IK'.

[0103] The key derivation process of the subsequent two authentication methods is similar. AUSF derives the anchor key KSEAF based on KAUSF and sends KSEAF to the security anchor function (SEAF) network element (SEAF for short). SEAF derives KAMF through KSEAF. Among them, SEAF can be part of AMF or an independent functional network element, which is not limited in this application.

[0104] Furthermore, AMF is based on K AMF Derive NAS confidentiality key K NASenc , NAS integrity protection key K NASint AMF also based on K AMF Derived K gNB , and K gNB and NH (next hop) are sent to gNB. gNB will send K gNB The RRC key and user plane key are deduced from NH. Among them, the RRC key includes the RRC confidentiality key K RRCenc and RRC integrity protection key K RRCint , the user plane key includes the user plane confidentiality key K UPenc and user plane integrity protection key K UPint For non-3GPP access, AMF also uses K AMF Derived K N3IWF , and K N3IWF Sent to N3IWF to protect subsequent non-3GPP access data traffic.

[0105] On the terminal device side, the terminal device includes a USIM and mobile equipment (ME). Similar to the key derivation process on the service network side, the key derivation process is completed by the ME.

[0106] The following is a brief introduction to the key deduction and key usage scenarios involved in this application:

[0107] (1) AMF according to K AMFDerived K gNB Required input parameters.

[0108] It is understandable that AMF and ME in UE use the same method according to K AMF Deduced K gNB For example, according to K AMF Derived K gNB The input parameters are as follows:

[0109] FC=0x6E;

[0110] P0 = uplink NAS counter value (uplink NAS COUNT);

[0111] L0 = length of the uplink NAS counter value;

[0112] P1 = access type distinguisher;

[0113] L1 = length of the access type identifier.

[0114] The value of P1 can be as shown in Table 1.

[0115] Table 1

[0116] From the above, we can see that K gNB =KDF(FC, P0, L0, P1, L1), where KDF is the abbreviation of Key Derivation Function (KDF). The access type identifier (ie, P1) can be used to distinguish 3GPP access from non-3GPP access.

[0117] (2) Use of integrity protection keys and confidentiality keys

[0118] Figure 3A shows the process of protecting a message using a confidentiality key. Figure 3B shows the process of protecting a message using an integrity key. As can be seen from Figures 3A and 3B, the left side of the dotted line represents the sender, and the right side of the dotted line represents the receiver.

[0119] In Figure 3A, when protecting a message, in addition to the confidentiality key, the following input parameters are also required: counter value, bearer parameter, direction parameter, and length parameter. NASenctWhen the bearer parameter is a NAS connection identifier, the NAS connection identifier is the same as the access type identifier. The direction parameter takes a value of 0 for uplink and a value of 1 for downlink. When the direction parameter indicates uplink, the counter takes the value of the uplink NAS counter. When the direction parameter indicates downlink, the counter takes the value of the downlink NAS counter.

[0120] Similarly, in FIG3B , when protecting a message, in addition to the integrity protection key, the following input parameters are also required: counter value, message parameter, direction parameter, and bearer parameter. NASint When the bearer parameter is NAS connection identifier, the NAS connection identifier is the same as the access type identifier.

[0121] The same terminal device can access both 3GPP and non-3GPP access networks at the same time. When using the access traffic steering, switching, splitting (ATSSS) function, the terminal device establishes a special protocol data unit (PDU) session: a multi-access PDU session (MA PDU) session. This session supports multiple accesses, and the data in this session can be transmitted on different access paths. The terminal device side needs to support multiple steering functions, namely: multipath TCP (MPTCP) function, multipath QUIC (MPQUIC) function and ATSSS-low layer (LL) function. TCP is the abbreviation of transmission control protocol (TCP). QUIC is the abbreviation of quick UDP internet connection (QUIC). UDP is the abbreviation of user datagram protocol (UDP). Each steering function in the terminal device allows steering, switching and diversion of service traffic across 3GPP access and non-3GPP access according to the ATSSS rules provided by the network.

[0122] Currently, the multi-access scenario supports one 3GPP access and one non-3GPP access. Among them, the multi-access scenario can also be called a multi-registration scenario. After receiving the registration request message, the AMF checks whether the terminal device has passed the network authentication. If an available security context for the terminal device is retrieved through the 5G globally unique temporary identifier (5G-GUTI), the AMF may decide not to run a new authentication. Exemplarily, the available security context of the terminal device is a public 5G NAS security context, which can also be called a public NAS security context.

[0123] For example, if a terminal device first registers to an AMF via 3GPP access, and the terminal device then registers to the same AMF via non-3GPP access, and the AMF retrieves the 5G NAS security context for the terminal device via 5G-GUTI, the AMF may decide not to run a new authentication. In this case, the terminal device also directly uses the 5G NAS security context and uses it to protect the registration for the non-3GPP access. If the NAS count of the non-3GPP access of the PLMN is stored in the terminal device, the stored NAS count of the non-3GPP access of the PLMN shall be used to protect the registration for the non-3GPP access. If the NAS count of the non-3GPP access of the PLMN is not stored in the terminal device, the 5G NAS security context will be used for the first time (partially) via non-3GPP access. In this case, before the terminal device uses the 5G NAS security context on the non-3GPP access, the terminal device needs to set the UL NAS count value and DL NAS count value of the non-3GPP access to zero.

[0124] The AMF and the terminal device shall establish a common NAS security context consisting of a set of NAS keys and algorithms during the first registration. The AMF and the terminal device shall also store parameters specific to each NAS connection in the common NAS security context. To achieve key separation and anti-replay protection, the parameters for each NAS connection include a pair of NAS counts for uplink and downlink and a unique NAS connection identifier. For example, for 3GPP access, the value of the unique NAS connection identifier shall be set to "0x01", and for non-3GPP access, the value of the unique NAS connection identifier shall be set to "0x02". Other parameters in the common NAS security context, such as the algorithm identifier, are common to multiple NAS connections.

[0125] Currently, the multi-access scenario does not support two 3GPP accesses. Therefore, how the MA PDU session supports at least two 3GPP accesses has become an issue worthy of attention. The two 3GPP access paths can be in the same PLMN or in different PLMNs. Among them, the two 3GPP access paths can use the same standard or different standards. For example, they can include the following cases: terrestrial NR + terrestrial NR; terrestrial NR + terrestrial evolved universal mobile communications system terrestrial radio access (E-UTRA) (for example, using a combination of evolved packet core (EPC) and 5G Core Network (5GC)); terrestrial NR + non-terrestrial NR; dual non-terrestrial NR (for example, using the same or different non-terrestrial networks (NTN) orbits, such as earth observation orbits, medium orbits, or low orbits). Unless otherwise specified, this application mainly discusses a multi-access scenario in which a terminal device is connected to the same PLMN via two 3GPP access paths, and does not limit whether the two 3GPP access paths are of the same standard. FIG4 is a schematic diagram of a terminal device connected to the same PLMN via two 3GPP access paths. It should be noted that this application uses the dual 3GPP access scenario as an example for illustration, and this application can also be applied to multi-3GPP access scenarios, such as scenarios with two or more 3GPP accesses, wherein dual 3GPP access can also be replaced by multi-3GPP access.

[0126] When a multi-access scenario supports one 3GPP access and one non-3GPP access, both accesses use the same K AMF Perform key derivation, where for 3GPP access, use K AMF Deduced K gNB For non-3GPP access, use K AMF Deduced K N3IWF . In the deduction process of the above two keys, the input parameters include the access type identifier (i.e. P1), which is used to distinguish 3GPP access from non-3GPP access. It can be seen that the current access type identifier (i.e. P1) cannot distinguish between two 3GPP accesses. Therefore, when a terminal device connects to the same PLMN through two 3GPP accesses, if only one primary authentication is performed, the two 3GPP accesses may not be distinguished, resulting in the use of the same key for the two 3GPP accesses, that is, the key reuse problem.

[0127] Based on the network system architecture shown in FIG1 and the contents of the above-mentioned related technical introduction, several possible communication methods are provided in the embodiments of the present application. The execution subjects of each key derivation method are introduced using the access and mobility management network element and the terminal device as examples. It should be understood that the access and mobility management network element can also be replaced by a communication device having the functions of the access and mobility management network element or a chip, unit or module inside the communication device having the functions of the access and mobility management network element. The terminal device can also be replaced by a communication device having terminal functions or a chip, unit or module inside the communication device having terminal functions.

[0128] In an embodiment of the present application, a terminal device sends a first registration request message and a second registration request message to an access and mobility management network element, wherein the first registration request message is used to request the terminal device to register with the network through a first 3GPP access. The second registration request message is used to request the terminal device to register with the network through a second 3GPP access. Furthermore, the access and mobility management network element and the terminal device generate a first key for the first 3GPP access and a second key for the second 3GPP access. The first key is different from the second key, the first key is a key used for communication between the terminal device and the first access network device, and the second key is a key used for communication between the terminal device and the second access network device. The access and mobility management network element sends the first key to the first access network device and sends the second key to the second access network device. Using the above method, two different keys are generated for the two 3GPP accesses to achieve key isolation.

[0129] In one possible implementation, the terminal device and the first access network device may communicate using a first key, or a key derived from the first key, and the terminal device and the second access network device may communicate using a second key, or a key derived from the second key.

[0130] Exemplarily, when the terminal device communicates with the first access network device, the terminal device and the first access network device may generate a first RRC key and a first user plane key based on the first key. The first RRC key includes a first RRC integrity protection key and / or a first RRC confidentiality key. The first user plane key includes a first user plane integrity protection key and / or a first user plane confidentiality key. Furthermore, the terminal device and the first access network device may perform security protection on the first RRC signaling based on the first RRC key, and / or the terminal device and the first access network device may perform security protection on the first data based on the first user plane key. The first RRC signaling is the RRC signaling sent by the terminal device to the first access network device, or the RRC signaling sent by the first access network device to the terminal device. The first data is the uplink data sent by the terminal device to the first access network device, or the downlink data sent by the first access network device to the terminal device.

[0131] Similarly, when the terminal device communicates with the second access network device, the terminal device and the second access network device can generate a second RRC key and a second user plane key based on the second key. The second RRC key includes a second RRC integrity protection key and / or a second RRC confidentiality key. The second user plane key includes a second user plane integrity protection key and / or a second user plane confidentiality key. Furthermore, the terminal device and the second access network device can perform security protection on the second RRC signaling based on the second RRC key, and / or the terminal device and the second access network device can perform security protection on the second data based on the second user plane key. The second RRC signaling is the RRC signaling sent by the terminal device to the second access network device, or the RRC signaling sent by the second access network device to the terminal device. The second data is the uplink data sent by the terminal device to the second access network device, or the downlink data sent by the second access network device to the terminal device.

[0132] As shown in Figures 5 to 8, the above process is described below with reference to specific examples. In each of the following examples, the terminal device is a UE, the access and mobility management network element is an AMF, the first access network device is RAN1, and the second access network device is RAN2.

[0133] Example 1:

[0134] S501: The UE sends a first registration request message to the AMF via RAN1. Correspondingly, the AMF receives the first registration request message.

[0135] The first registration request message is used to request the UE to register with the network through the first 3GPP access.

[0136] Exemplarily, the UE sends a first Registration Request message to RAN1. RAN1 selects an AMF and sends the first Registration Request message to the AMF. Optionally, if the UE has previously registered with another AMF (i.e., the source AMF), the AMF obtains the previous UE context from the source AMF. If the UE has not registered with another AMF, RAN1 performs the AMF discovery and selection process.

[0137] For example, the AMF can also trigger the main authentication process to complete the authentication of the network side to the UE and the UE to the network side, and the network side deduces the key K AMF , determine the key K AMF The corresponding key set identifier (key set identifier in 5g, ngKSI). AMF The deduction process can refer to the above related content, which will not be repeated here. ngKSI is used to identify the key K established by the main authentication process. AMFIf the UE identity authentication is successful, ngKSI can also be used to identify the partial security context created by the UE. For example, ngKSI can identify the corresponding key K AMF , the values ​​of uplink and downlink NAS counters, etc.

[0138] As shown in Figure 2, the UE can also deduce the key K AMF . Further, AMF and UE can AMF Derive NAS confidentiality key K NASenc and / or NAS integrity protection key K NASint Among them, the NAS confidentiality key K NASenc and / or NAS integrity protection key K NASint It can be stored in the UE's security context. In this application, the NAS confidentiality key K NASenc and NAS integrity protection key K NASint Both the NAS security protection key and the AMF key can be referred to as NAS keys.

[0139] S502: The AMF generates a first key according to the first access type identifier.

[0140] In one possible implementation, before generating the first key, the AMF determines a first access type identifier for the first 3GPP access. The first access type identifier may be stored in the UE's security context. Exemplarily, the AMF further creates a pair of NAS counters for the first NAS connection corresponding to the first 3GPP access and sets them to initial values. The AMF stores parameters of the first NAS connection in the UE's security context. The parameters of the first NAS connection include the first access type identifier and the pair of NAS counters.

[0141] In one example, before generating the first key, the AMF determines the first access type identifier, and the UE also determines the first access type identifier. The AMF and the UE may agree in advance on the first allocated access type identifier through a protocol to ensure that the same first access type identifier is allocated to both.

[0142] In another example, the AMF determines a first access type identifier and sends the first access type identifier to RAN1. RAN1 notifies the UE through a first access stratum (AS) security mode command (AS security mode command) carrying the first access type identifier.

[0143] In another example, the AMF determines a first access type identifier and carries the first access type identifier in a first registration accept message to notify the UE.

[0144] For example, as shown in Table 2, the first access type identifier may be 0x01 or 0x03.

[0145] Table 2

[0146] It is understandable that the above values ​​0x01 and 0x03 are only examples, and other currently undefined values, such as 0x11, can also be used through extension, which is not limited here.

[0147] In one possible implementation, after determining the first access type identifier, the AMF AMF ) and the first access type identifier to generate a first key. The first key can be recorded as K gNB 1. It is understandable that the generation of the first key also requires the combination of other parameters, such as K gNB 1=KDF(FC, P0, L0, P1, L1), where P0=the uplink NAS counter value corresponding to the first 3GPP access, L0=the length of the uplink NAS counter value corresponding to the first 3GPP access, P1=the first access type identifier, and L1=the length of the first access type identifier. For details, please refer to the above related content and will not be repeated here.

[0148] Exemplarily, the AMF may also send a first registration accept message to the UE through RAN1, where the first registration accept message includes a 5G GUTI. The 5G GUTI is allocated by the AMF to the UE. Optionally, the first registration accept message includes a first access type identifier.

[0149] In addition, the AMF may also send a NAS security mode command (NAS security mode command) to the UE via RAN1, where the NAS security mode command includes the ngKSI. The UE may also reply to the AMF with a NAS security mode complete message via RAN1.

[0150] S503: The AMF sends the first key to RAN1. Correspondingly, RAN1 receives the first key from the AMF.

[0151] For example, RAN1 may receive the first key (eg, K gNB 1) Generate a first RRC key and a first user plane key. For example, the first RRC key includes K RRCenc 1 and / or K RRCint 1. The first user plane key includes K UPenc 1 and / or K UPint 1.

[0152] Optionally, the AMF may also send a first access type identifier to RAN1. In addition, RAN1 may also send a first AS security mode command to the UE. The first AS security mode command is used to notify the UE of the RRC signaling protection cipher algorithm and / or user plane protection cipher algorithm selected by the network side. Optionally, the first AS security mode command may also include the first access type identifier. Furthermore, after the UE executes S504 to generate the first key, the UE may also send a first AS security mode response to RAN1. In addition, RAN1 may also use other signaling to carry the first access type identifier, which is not limited in this application.

[0153] S504: The UE generates a first key according to the first access type identifier.

[0154] In a possible implementation, before generating the first key, the UE may determine a first access type identifier for the first 3GPP access.

[0155] In one example, the UE determines the first access type identifier by itself. The AMF and the UE may agree in advance on the first allocated access type identifier through a protocol to ensure that the same first access type identifier is allocated to both.

[0156] In another example, the UE receives a first registration accept message from the AMF, where the first registration accept message includes a first access type identifier.

[0157] In another example, the UE receives a first AS security mode command from RAN1, where the first AS security mode command includes a first access type identifier.

[0158] In addition, the UE creates a pair of NAS counters for a first NAS connection corresponding to the first 3GPP access and sets them to initial values. The UE stores parameters of the first NAS connection, which are stored in the UE's security context. The parameters of the first NAS connection include the first access type identifier and the pair of NAS counters.

[0159] In one possible implementation, the UE sends the AMF key (e.g., K AMF ) and the first access type identifier to generate a first key, namely K gNB 1, a first RRC key and a first user plane key may be further generated based on the first key. The method for generating the first key by the AMF and the UE is the same and will not be repeated here. The AMF key here is the same as the AMF key mentioned in S502, both of which are keys K AMF .

[0160] It is understandable that the present application does not limit the order of S502, S503 and S504.

[0161] Therefore, when RAN1 communicates with the UE, RAN1 and the UE may use the first RRC key to securely protect the first RRC signaling and / or use the first user plane key to securely protect the first data.

[0162] S505: The UE sends a second registration request message to the AMF. Correspondingly, the AMF receives the second registration request message.

[0163] The second registration request message is used to request the UE to register with the network through the second 3GPP access.

[0164] Exemplarily, the second registration request message includes indication information, wherein the indication information is used to instruct the UE to connect to the network through two 3GPP accesses. It can also be described as that the indication information is used to instruct the UE to register with the network through two 3GPP accesses.

[0165] It is understood that the indication information may also be used to instruct the UE to connect to the network via multiple 3GPP accesses, or the UE to register with the network via multiple 3GPP accesses, wherein multiple 3GPP accesses may be understood as two or more 3GPP accesses.

[0166] For example, the indication information may indicate that the registration type (registration type) is dual 3GPP registration, or the indication information may indicate that the access type (access type) is dual 3GPP access.

[0167] For another example, the indication information may indicate that the registration type is multi-3GPP registration, or the indication information may indicate that the access type is multi-3GPP access.

[0168] In addition, the second registration request message may also include 5G-GUTI. Optionally, the second registration request message may also include ngKSI. The UE may also use the NAS integrity protection key K NASint The second registration request message is integrity protected. It can be understood that, in combination with the above S501, the NAS integrity protection key K NASint According to K AMF Derived, NAS integrity protection key K NASint Saved in the UE's security context.

[0169] Exemplarily, the UE sends a second registration request message to RAN2. RAN2 obtains the AMF identifier based on 5G-GUTI, and RAN2 forwards the second registration request message to AMF. For example, the AMF identifier is a globally unique AMF identifier (GUAMI), <5G-GUTI> = <guami>+<5G-TMSI>, the identity of the PLMN to which the UE is registered is also provided in the GUAMI of the 5G-GUTI. For example, the mobile country code (MCC) and mobile network code (MNC) are also included in the GUAMI.

[0170] After receiving the second registration request message, the AMF can retrieve the security context of the UE in the AMF according to the 5G-GUTI (and ngKSI) in the second registration request message, and use the NAS integrity protection key K in the security context of the UE NASint , verify the integrity of the second registration request message, thereby completing the identity authentication of the UE.

[0171] S506: The AMF generates a second key according to the second access type identifier.

[0172] In one possible implementation, after the AMF successfully authenticates the UE and before generating the second key, the AMF determines the second access type identifier for the second 3GPP access according to the indication information.

[0173] Exemplarily, the AMF determines a second access type identifier for the second 3GPP access based on the indication information and the first access type identifier, which is different from the first access type identifier. Using the above approach, the AMF can determine, based on the indication information, that the UE is connected to the network via two 3GPP accesses, and then obtain the first access type identifier based on the UE's security context. The AMF determines a second access type identifier for the second 3GPP access, where the second access type identifier is an unused access type identifier. The first access type identifier is different from the second access type identifier.

[0174] For example, as shown in Table 2, if the first access type identifier is 0x01, the second access type identifier is 0x03. If the first access type identifier is 0x03, the second access type identifier is 0x01.

[0175] In addition, the AMF creates a pair of NAS counters for the second NAS connection corresponding to the second 3GPP access and sets them to initial values. The AMF saves the parameters of the second NAS connection in the UE's security context. The parameters of the second NAS connection include the second access type identifier and the pair of NAS counters.

[0176] It can be understood that the AMF maintains a set of UE security contexts for the first 3GPP access and the second 3GPP access. The UE security context includes two sets of NAS connection parameters. The parameters of the first NAS connection include a first access type identifier and a pair of NAS counters. The parameters of the second NAS connection include a second access type identifier and a pair of NAS counters.

[0177] In one possible implementation, after determining the second access type identifier, the AMF sends the second access type identifier to the AMF according to the AMF key (e.g., K AMF ) and the second access type identifier to generate a second key. The second key can be recorded as K gNB 2. The AMF key here is the same as the AMF key mentioned in S502 and S504 above, both of which are key K AMF It is understandable that the generation of the second key also needs to be combined with other parameters, such as K gNB 2=KDF(FC, P0, L0, P1, L1), where P0=the uplink NAS counter value corresponding to the second 3GPP access, L0=the length of the uplink NAS counter value corresponding to the second 3GPP access, P1=the second access type identifier, and L1=the length of the second access type identifier.

[0178] In addition, the AMF may also send a second registration acceptance message to the UE. Optionally, the second registration acceptance message may include a second access type identifier.

[0179] S507: The AMF sends the second key to RAN2. In response, RAN2 receives the second key from the AMF.

[0180] For example, RAN2 may use the received second key (eg, K gNB 2) Generate a second RRC key and a second user plane key. For example, the second RRC key includes K RRCenc 2 and K RRCint 2. The second user plane key includes K UPenc 2 and K UPint 2.

[0181] Optionally, the AMF may also send a second access type identifier to RAN2. In addition, RAN2 may also send a second AS security mode command to the UE. The second AS security mode command is used to notify the UE of the RRC signaling protection cipher algorithm and / or user plane protection cipher algorithm selected by the network side. Optionally, the second AS security mode command may also include the second access type identifier. Furthermore, after the UE executes S508 to generate the second key, the UE may also send a second AS security mode response to RAN2. In addition, RAN2 may also use other signaling to carry the second access type identifier, which is not limited in this application.

[0182] S508: The UE generates a second key according to the second access type identifier.

[0183] In a possible implementation, before the UE generates the second key, the UE determines a second access type identifier for the second 3GPP access.

[0184] In one example, the UE determines a second access type identifier for the second 3GPP access based on the first access type identifier in the UE's security context. Exemplarily, the UE determines that the first access type identifier has been used by the first 3GPP access and allocates an unused second access type identifier to the second 3GPP access. At this point, since the AMF and the UE have already agreed in advance on the first allocated access type identifier through a protocol, and there are two access type identifiers used to identify 3GPP accesses as shown in Table 2, it can be ensured that the second allocated second access type identifiers for the two are also the same.

[0185] In another example, the AMF sends a second registration accept message to the UE, where the second registration accept message includes the second access type identifier. Therefore, the UE can determine the second access type identifier based on the second registration accept message.

[0186] In another example, the AMF sends a second access type identifier to RAN2, and RAN2 sends a second AS security mode command to the UE, where the second AS security mode command includes the second access type identifier. Therefore, the UE can determine the second access type identifier based on the second AS security mode command.

[0187] In addition, the UE creates a pair of NAS counters for the second NAS connection corresponding to the second 3GPP access and sets them to initial values. The UE saves parameters of the second NAS connection, which include the second access type identifier and the pair of NAS counters.

[0188] It can be understood that the UE maintains a set of UE security contexts for the first 3GPP access and the second 3GPP access, and the UE security context includes two sets of NAS connection parameters, the parameters of the first NAS connection include a first access type identifier and a pair of NAS counters, and the parameters of the second NAS connection include a second access type identifier and a pair of NAS counters.

[0189] In one possible implementation, the UE sends the AMF key (e.g., K AMF ) and the second access type identifier to generate a second key, namely K gNB 2. A second RRC key and a second user plane key may be further generated based on the second key. The method for AMF and UE to generate the second key is the same. The AMF key here is the same as the AMF key mentioned in S502, S504 and S506 above, both of which are keys K AMF .

[0190] It is understandable that the present application does not limit the order of S506, S507 and S508.

[0191] Therefore, when RAN2 communicates with the UE, RAN2 and the UE may use the second RRC key to protect the second RRC signaling, and use the second user plane key to protect the second data.

[0192] By adopting the above method, by using different access type identifiers in two 3GPP access processes, it is possible to ensure that the first key and the second key are different, thereby achieving key isolation.

[0193] Example 2:

[0194] S601: The UE sends a first registration request message to the AMF via RAN1. Correspondingly, the AMF receives the first registration request message.

[0195] For the specific content of S601, please refer to the above S501.

[0196] The difference from the above S501 is that the first registration request message includes indication information, wherein the indication information can refer to the relevant content in the above S505.

[0197] S602: The AMF generates a first key according to the first access type identifier.

[0198] In one possible implementation, before generating the first key, the AMF determines a first access type identifier for the first 3GPP access based on the indication information, where the first access type identifier is one of the dual 3GPP access type identifiers. The first access type identifier may be stored in the security context of the UE. Exemplarily, the AMF determines, based on the indication information, that the UE is connected to the network via two 3GPP accesses, then determines one of the dual 3GPP access type identifiers for the first 3GPP access as the first access type identifier, creates a pair of NAS counters, and sets them to initial values. The AMF stores the parameters of the first NAS connection corresponding to the first 3GPP access in the security context of the UE. The parameters of the first NAS connection include the first access type identifier and a pair of NAS counters.

[0199] The dual 3GPP access type identifier is a newly defined access type identifier. Its value is different from the access type identifier previously used to identify 3GPP access. The dual 3GPP access type identifier is used in multi-3GPP access or dual 3GPP access scenarios. The dual 3GPP access type identifier can also be called a multi-3GPP access type identifier. Generally, the dual 3GPP access type identifier can include two or more.

[0200] Table 3 shows a possible implementation of dual 3GPP access type identifiers. As shown in Table 3, the first access type identifier may be 0x03 or 0x04.

[0201] Table 3

[0202] It is understandable that the above values ​​0x03 and 0x04 are only examples, and other currently undefined values ​​can also be used through extension, which is not limited here.

[0203] In one example, before generating the first key, the AMF determines the first access type identifier, and the UE also determines the first access type identifier. In this case, the AMF and the UE may agree in advance on the first allocated identifier of the dual 3GPP access type identifiers through a protocol to ensure that the same identifier is allocated to both.

[0204] In another example, the AMF determines a first access type identifier and notifies the UE of the first access type identifier through a first registration accept message.

[0205] In another example, the AMF determines the first access type identifier and sends the first access type identifier to RAN1. RAN1 carries the first access type identifier through the first AS security mode command to notify the UE.

[0206] In addition, in a possible implementation, a new field may be added to the security context of the UE. For example, the field is recorded as the first field. Exemplarily, the first field may include 1 bit. The value of the 1 bit is 1, indicating that the UE is connected to the network through two 3GPP accesses, or the access type (or registration type) of the UE is dual 3GPP access or multi-3GPP access. The value of the 1 bit is 0, indicating that the UE is not connected to the network through two 3GPP accesses, or the access type (or registration type) of the UE is non-dual 3GPP access or non-multi-3GPP access. The AMF may determine the value of the first field based on the indication information.

[0207] In one possible implementation, after determining the first access type identifier, the AMF AMF ) and the first access type identifier to generate a first key. The first key can be recorded as K gNB 1, for example, K gNB 1=KDF(FC, P0, L0, P1, L1, P2, L2), P0=the uplink NAS counter value corresponding to the first 3GPP access, L0=the length of the uplink NAS counter value corresponding to the first 3GPP access, P1=the first access type identifier, L1=the length of the first access type identifier.

[0208] In addition, the AMF may also send a first registration acceptance message to the UE through RAN1. Optionally, the first registration acceptance message includes a first access type identifier.

[0209] S603: The AMF sends the first key to RAN1. In response, RAN1 receives the first key from the AMF.

[0210] For example, RAN1 may receive the first key (eg, K gNB 1) Generate a first RRC key and a first user plane key. For example, the first RRC key includes K RRCenc 1 and / or K RRCint 1. The first user plane key includes K UPenc 1 and / or K UPint 1.

[0211] Optionally, the AMF may also send a first access type identifier to RAN1. In addition, RAN1 may also send a first AS security mode command to the UE. The first AS security mode command is used to notify the UE of the RRC signaling protection cipher algorithm and / or user plane protection cipher algorithm selected by the network side. Optionally, the first AS security mode command may also include the first access type identifier. Furthermore, after the UE generates the first key in S604, the UE may also send a first AS security mode response to RAN1.

[0212] S604: The UE generates a first key according to the first access type identifier.

[0213] In a possible implementation, before generating the first key, the UE may determine a first access type identifier for the first 3GPP access.

[0214] In one example, the UE knows that it is connected to the network through two 3GPP accesses, and the first 3GPP access is the first 3GPP access. Before generating the first key, the UE determines a first access type identifier for the first 3GPP access, and the first access type identifier is one of the dual 3GPP access type identifiers.

[0215] In another example, the UE receives a first registration accept message from the AMF, where the first registration accept message includes a first access type identifier.

[0216] In another example, the UE receives a first AS security mode command from RAN1, where the first AS security mode command includes a first access type identifier.

[0217] In addition, the UE creates a pair of NAS counters for a first NAS connection corresponding to the first 3GPP access and sets them to initial values. The UE stores parameters of the first NAS connection, which are stored in the UE's security context. The parameters of the first NAS connection include the first access type identifier and the pair of NAS counters.

[0218] Furthermore, in a possible implementation, the UE sends a key to the AMF (e.g., K AMF ) and the first access type identifier to generate a first key, namely K gNB 1, the first RRC key and the first user plane key can be further generated based on the first key. The method for generating the first key by AMF and UE is the same, which will not be repeated here. The AMF key here is the same as the AMF key mentioned in S602, both of which are keys K AMF .

[0219] It is understandable that the present application does not limit the order of S602, S603 and S604.

[0220] Therefore, when RAN1 communicates with the UE, RAN1 and the UE may use the first RRC key to securely protect the first RRC signaling, and use the first user plane key to securely protect the first data.

[0221] S605: The UE sends a second registration request message to the AMF. In response, the AMF receives the second registration request message.

[0222] The second registration request message is used to request the UE to register with the network through the second 3GPP access. Optionally, the second registration request message may also include indication information.

[0223] In addition, for other contents of the second registration request message, please refer to S505.

[0224] S606: The AMF generates a second key according to the second access type identifier.

[0225] In one possible implementation, after the AMF successfully authenticates the UE and before generating the second key, the AMF determines the second access type identifier for the second 3GPP access.

[0226] Exemplarily, the AMF may obtain a first access type identifier based on the security context of the UE. Since the first access type identifier is one of the dual 3GPP access type identifiers, the AMF determines that the UE is connected to the network through two 3GPP accesses; or, if the security context of the UE includes a first field, the AMF determines that the UE is connected to the network through two 3GPP accesses based on the first field in the security context of the UE; or, if the second registration request message includes indication information, the AMF determines that the UE is connected to the network through two 3GPP accesses based on the indication information.

[0227] Further, after the AMF determines that the UE is connected to the network through two 3GPP accesses, the AMF allocates a second access type identifier for the second 3GPP access, where the second access type identifier is another identifier in the dual 3GPP access type identifier, wherein the second access type identifier is an unused identifier in the dual 3GPP access type identifier. The first access type identifier is different from the second access type identifier.

[0228] In addition, the AMF creates a pair of NAS counters for the second NAS connection corresponding to the second 3GPP access and sets them to initial values. The AMF saves the parameters of the second NAS connection in the UE's security context. The parameters of the second NAS connection include the second access type identifier and the pair of NAS counters.

[0229] It can be understood that the AMF maintains a set of UE security contexts for the first 3GPP access and the second 3GPP access. The UE security context includes two sets of NAS connection parameters. The parameters of the first NAS connection include a first access type identifier and a pair of NAS counters. The parameters of the second NAS connection include a second access type identifier and a pair of NAS counters.

[0230] Further, in a possible implementation, after determining the second access type identifier, the AMF sends the second access type identifier according to the AMF key (for example, K AMF ) and the second access type identifier to generate a second key. The second key can be recorded as K gNB 2. It is understandable that the generation of the second key also requires the combination of other parameters, such as K gNB 2 = KDF (FC, P0, L0, P1, L1), where P0 = the uplink NAS counter value corresponding to the second 3GPP access, L0 = the length of the uplink NAS counter value corresponding to the second 3GPP access, P1 = the second access type identifier, and L1 = the length of the second access type identifier. The AMF key here is the same as the AMF key mentioned in S602 and S604 above, both of which are key K AMF .

[0231] In addition, the AMF may also send a second registration acceptance message to the UE. Optionally, the second registration acceptance message may include a second access type identifier.

[0232] S607: The AMF sends the second key to RAN2. In response, RAN2 receives the second key from the AMF.

[0233] For example, RAN2 may use the received second key (eg, K gNB 2) Generate a second RRC key and a second user plane key. For example, the second RRC key includes K RRCenc 2 and K RRCint 2. The second user plane key includes K UPenc 2 and K UPint 2.

[0234] Optionally, the AMF may also send a second access type identifier to RAN2. In addition, RAN2 may also send a second AS security mode command to the UE. The second AS security mode command is used to notify the UE of the RRC signaling protection cipher algorithm and / or user plane protection cipher algorithm selected by the network side. Optionally, the second AS security mode command may also include the second access type identifier. Furthermore, after the UE executes S608 to generate the second key, the UE may also send a second AS security mode response to RAN2.

[0235] S608: The UE generates a second key according to the second access type identifier.

[0236] In a possible implementation, before the UE generates the second key, the UE determines a second access type identifier for the second 3GPP access.

[0237] In one example, the UE determines to allocate a second access type identifier for the second 3GPP access based on the first access type identifier in the security context of the UE. The UE determines that the first access type identifier is one of the dual 3GPP access type identifiers, and allocates the other identifier in the dual 3GPP access type identifier as the second access type identifier for the second 3GPP access. The second access type identifier is an unused identifier in the dual 3GPP access type identifier. The first access type identifier is different from the second access type identifier. At this time, since the AMF and the UE have agreed in advance on the first allocated identifier in the dual 3GPP access type identifier through an agreement, and there are two identifiers for identifying the dual 3GPP access type as shown in Table 3, it can be further ensured that the second access type identifiers allocated for the second time by the two are also the same.

[0238] In another example, the AMF sends a second registration accept message to the UE, where the second registration accept message includes the second access type identifier. Therefore, the UE can determine the second access type identifier based on the second registration accept message.

[0239] In another example, the AMF sends a second access type identifier to RAN2, and RAN2 sends a second AS security mode command to the UE, where the second AS security mode command includes the second access type identifier. Therefore, the UE can determine the second access type identifier based on the second AS security mode command.

[0240] In addition, the UE creates a pair of NAS counters for the second NAS connection corresponding to the second 3GPP access and sets them to initial values. The UE saves parameters of the second NAS connection, which include the second access type identifier and the pair of NAS counters.

[0241] It can be understood that the UE maintains a set of UE security contexts for the first 3GPP access and the second 3GPP access, and the UE security context includes two sets of NAS connection parameters, the parameters of the first NAS connection include a first access type identifier and a pair of NAS counters, and the parameters of the second NAS connection include a second access type identifier and a pair of NAS counters.

[0242] In a possible implementation, the UE generates a second key, namely K according to the AMF key and the second access type identifier. gNB 2. A second RRC key and a second user plane key may be further generated based on the second key. The method for generating the second key by the AMF and the UE is the same and will not be repeated here. The AMF key here is the same as the AMF key mentioned in S602, S604 and S606 above, both of which are keys K AMF .

[0243] It is understandable that the present application does not limit the order of S606, S607 and S608.

[0244] Therefore, when RAN2 communicates with the UE, RAN2 and the UE may use the second RRC key to protect the second RRC signaling, and use the second user plane key to protect the second data.

[0245] By adopting the above method, by using different access type identifiers in two 3GPP access processes, it is possible to ensure that the first key and the second key are different, thereby achieving key isolation.

[0246] In addition, for the above Example 1 and Example 2, in addition, in one possible implementation, the AMF uses the NAS security protection key and the first bearer parameter to securely protect the first NAS signaling, where the first NAS signaling corresponds to the first 3GPP access, and uses the NAS security protection key and the second bearer parameter to securely protect the second NAS signaling, where the second NAS signaling corresponds to the second 3GPP access. The first bearer parameter is the first access type identifier, and the second bearer parameter is the first access type identifier.

[0247] Among them, from the above S501, it can be known that the NAS security protection key includes the NAS confidentiality key K NASenc and / or NAS integrity protection key K NASint The first NAS signaling is NAS signaling transmitted between the AMF and the UE via the first 3GPP access. The second NAS signaling is NAS signaling transmitted between the AMF and the UE via the second 3GPP access.

[0248] For example, AMF is calculated based on K AMF Derive NAS confidentiality key K NASenc , NAS integrity protection key K NASint , according to the NAS confidentiality key K NASenc and the first access type identifier to protect the confidentiality of the first NAS signaling, and protect the confidentiality of the first NAS signaling according to the NAS integrity protection key K NASint and the first access type identifier to perform integrity protection on the first NAS signaling, and NASenc The second NAS signaling is protected confidentially using the second access type identifier and the NAS integrity protection key K NASint The second NAS signaling is integrity protected by using the second access type identifier.

[0249] For example, as shown in FIG3A , for the first 3GPP access, according to the NAS confidentiality key K NASenc The AMF performs confidentiality protection on the first NAS signaling using the corresponding input parameters, where the input parameters include at least one of a first counter value, a first bearer parameter, a first direction parameter, and a first length parameter, and the first bearer parameter includes a first access type identifier. If the AMF performs confidentiality protection on the first NAS signaling, the first counter is the downlink NAS counter corresponding to the first 3GPP access, and the first direction parameter indicates downlink. If the UE performs confidentiality protection on the first NAS signaling, the first counter is the uplink NAS counter corresponding to the first 3GPP access, and the first direction parameter indicates uplink.

[0250] For the second 3GPP access, according to the NAS confidentiality key K NASenc The AMF performs confidentiality protection on the second NAS signaling using the corresponding input parameters, where the input parameters include at least one of a second counter value, a second bearer parameter, a second direction parameter, and a second length parameter, with the second bearer parameter including the second access type identifier. If the AMF performs confidentiality protection on the second NAS signaling, the second counter is the downlink NAS counter corresponding to the second 3GPP access, and the second direction parameter indicates downlink. If the UE performs confidentiality protection on the second NAS signaling, the second counter is the uplink NAS counter corresponding to the second 3GPP access, and the second direction parameter indicates uplink.

[0251] For another example, in conjunction with FIG3B , for the first 3GPP access, the AMF or UE protects the key K according to the NAS integrity NASint The second NAS signaling is integrity protected according to the corresponding input parameters, wherein the input parameters include at least one of the value of the first counter, the first bearer parameter, the first direction parameter, and the first message parameter, and the first bearer parameter includes the first access type identifier. For the second 3GPP access, the AMF or UE performs integrity protection according to the NAS integrity protection key K NASint And corresponding input parameters are used to perform integrity protection on the second NAS signaling, wherein the input parameters here include at least one of the value of the second counter, the second bearer parameter, the second direction parameter, and the second message parameter, and the second bearer parameter includes the second access type identifier.

[0252] In the above manner, by using different bearer parameters, the problem of key stream reuse caused by two 3GPPs using the same NAS key can be avoided.

[0253] Example 3:

[0254] S701: The UE sends a first registration request message to the AMF via RAN1. Correspondingly, the AMF receives the first registration request message.

[0255] For the specific content of S701, please refer to the above S501.

[0256] The difference from the above S501 is that the first registration request message includes indication information, wherein the indication information can refer to the relevant content in the above S505.

[0257] S702: The AMF generates a first key according to the third access type identifier and the identifier of the first 3GPP access.

[0258] In a possible implementation, before the AMF generates the first key, the AMF determines an identifier of the first 3GPP access for the first 3GPP access according to the indication information.

[0259] Exemplarily, the identifier of the first 3GPP access is the path identifier of the first 3GPP access, or other identifiers used to identify the first 3GPP access, wherein the identifier of the first 3GPP access is different from the access type identifier. Exemplarily, the path identifier of the first 3GPP access is the identifier of the data transmission path between the UE and the UPF. For example, taking the downlink data as an example, the downlink data from the DN arrives at UPF1, is forwarded to RAN1 through UPF2, and then RAN1 sends the downlink data to the UE, so the downlink data transmission path is UPF1→UPF2→RAN1→UE. Similarly, the uplink data transmission path is UE→RAN1→UPF2→UPF1, then the path identifier of the first 3GPP access is an identifier used to identify the uplink data transmission path and / or the downlink data transmission path. Exemplarily, the AMF determines the identifier of the first 3GPP access for the first 3GPP access based on the indication information, which may include but is not limited to the following methods:

[0260] Method a: The AMF may allocate the first 3GPP access identifier for the first 3GPP access based on the indication information. In this case, the AMF also needs to send the first 3GPP access identifier to the UE. For example, the AMF sends a first registration accept message to the UE, where the first registration accept message includes the first 3GPP access identifier. Alternatively, the AMF sends the first 3GPP access identifier to RAN1, and RAN1 notifies the UE of the first 3GPP access identifier via a first AS security mode command.

[0261] Method b: The AMF may obtain the identifier of the first 3GPP access from other core network elements. Furthermore, the AMF needs to send the identifier of the first 3GPP access to the UE. For example, the AMF sends a first registration accept message to the UE, where the first registration accept message includes the identifier of the first 3GPP access. Alternatively, the AMF sends the identifier of the first 3GPP access to RAN1, which then notifies the UE of the identifier of the first 3GPP access via a first AS security mode command carrying the identifier of the first 3GPP access.

[0262] Exemplarily, the AMF may obtain two 3GPP access identifiers from the UDM. For example, the UDM configures two 3GPP access identifiers in the subscription information when the UE is connected to the network through two 3GPP accesses, and the two 3GPP access identifiers are different. The Nudm_UECM_Registration request message sent by the AMF to the UDM includes the content of the indication information. The UDM may then obtain the two 3GPP access identifiers from the subscription information according to the content of the indication information and send them to the AMF. The AMF uses one of the two 3GPP access identifiers received as the identifier of the first 3GPP access.

[0263] In one example, the UDM may also indicate an allocation order of the two 3GPP access identifiers, and the AMF may determine an identifier of the first 3GPP access for the first 3GPP access from the two 3GPP access identifiers according to the allocation order.

[0264] In another example, if the two 3GPP access identifiers replied by the UDM do not indicate the allocation order, the AMF may determine the first 3GPP access identifier for the first 3GPP access from the two 3GPP access identifiers. For example, the AMF may randomly select one of the two 3GPP access identifiers as the identifier of the first 3GPP access.

[0265] Further, after the AMF determines the identifier of the first 3GPP access, the AMF may store the identifier of the first 3GPP access in the security context of the UE. In addition, the identifier of another 3GPP access that has not yet been allocated may also be stored in the security context of the UE.

[0266] Mode c: The first registration request message includes the identifier of the first 3GPP access, that is, the UE determines the identifier of the first 3GPP access.

[0267] Exemplarily, after determining the identifier of the first 3GPP access, the AMF may store the identifier of the first 3GPP access in the security context of the UE. In addition, the AMF creates a pair of NAS counters for the first NAS connection corresponding to the first 3GPP access and sets them to initial values.

[0268] In one possible implementation, the AMF sends a AMF ), the third access type identifier and the first 3GPP access identifier generate a first key. The third access type identifier is the access type identifier for identifying 3GPP access shown in Table 1. Combined with Table 1, it can be seen that the access type identifier here can be 0x01, and the first key can be recorded as K gNB1 .

[0269] In one example, the identifier of the first 3GPP access is used as the identifier for generating K gNB1 The new input parameters, then K gNB 1=KDF(FC, P0, L0, P1, L1, P2, L2), P0=the uplink NAS counter value corresponding to the first 3GPP access, L0=the length of the uplink NAS counter value corresponding to the first 3GPP access, P1=the third access type identifier, L1=the length of the third access type identifier, P2 is the identifier of the first 3GPP access, and L2 is the length of the identifier of the first 3GPP access.

[0270] In another example, the definition of P1 is updated, and P1 is determined according to the first 3GPP access identifier and the third access type identifier. For example, the result of concatenating the first 3GPP access identifier and the third access type identifier is taken as P1. Then K gNB 1=KDF(FC, P0, L0, P1, L1), P0=uplink NAS counter value corresponding to the first 3GPP access, L0=length of the uplink NAS counter value corresponding to the first 3GPP access, P1=third access type identifier||identifier of the first 3GPP access, L1=third access type identifier||length of the identifier of the first 3GPP access.

[0271] In another example, the definition of P1 is updated, and P1 is determined according to the identifier of the first 3GPP access. For example, the identifier of the first 3GPP access is used as P1, then K gNB 1=KDF(FC, P0, L0, P1, L1), P0=the uplink NAS counter value corresponding to the first 3GPP access, L0=the length of the uplink NAS counter value corresponding to the first 3GPP access, P1=the identifier of the first 3GPP access, and L1=the length of the identifier of the first 3GPP access.

[0272] It is understood that the above examples are only examples and are not intended to limit the present application. K can be generated by taking the uplink NAS counter value corresponding to the first 3GPP access, the length of the uplink NAS counter value corresponding to the first 3GPP access, the identifier of the first 3GPP access, the length of the identifier of the first 3GPP access, the third access type identifier, and one or more parameters of the length of the third access type identifier. gNB 1.

[0273] In a possible implementation, a new field may be added to the security context of the UE. For example, the field is recorded as the first field. Exemplarily, the first field may include 1 bit. If the value of the 1 bit is 1, it indicates that the UE is connected to the network through two 3GPP accesses, or the access type (or registration type) of the UE is dual 3GPP access or multi-3GPP access. If the value of the 1 bit is 0, it indicates that the UE is not connected to the network through two 3GPP accesses, or the access type (or registration type) of the UE is non-dual 3GPP access or non-multi-3GPP access. The AMF may determine the value of the first field based on the indication information.

[0274] In addition, the AMF may also send a first registration acceptance message to the UE through RAN1. Optionally, the first registration acceptance message includes an identifier of the first 3GPP access.

[0275] S703: The AMF sends the first key to RAN1. In response, RAN1 receives the first key from the AMF.

[0276] For example, RAN1 may receive the first key (eg, K gNB 1) Generate a first RRC key and a first user plane key. For example, the first RRC key includes K RRCenc 1 and K RRCint 1. The first user plane key includes K UPenc 1 and K UPint 1.

[0277] Optionally, the AMF may also send a first access type identifier to RAN1. In addition, RAN1 may also send a first AS security mode command to the UE. The first AS security mode command is used to notify the UE of the RRC signaling protection cipher algorithm and / or user plane protection cipher algorithm selected by the network side. Optionally, the first AS security mode command may also include the first access type identifier. Furthermore, after the UE generates the first key in S704, the UE may also send a first AS security mode response to RAN1.

[0278] S704: The UE generates a first key according to the third access type identifier and the identifier of the first 3GPP access.

[0279] In one possible design, the UE determines an identifier of the first 3GPP access before generating the first key.

[0280] In one example, the UE knows that it is connected to the network via two 3GPP accesses, and the first 3GPP access is a first 3GPP access. Therefore, before generating the first key, the UE determines the first 3GPP identifier for the first 3GPP access. For example, the UE can determine the identifier of the first 3GPP access itself. In this case, the first registration request message can include the identifier of the first 3GPP access.

[0281] In another example, the UE receives a first registration accept message from the AMF, where the first registration accept message includes an identifier of the first 3GPP access.

[0282] In yet another example, the UE receives a first AS security mode command from RAN1, where the first AS security mode command includes an identifier of a first 3GPP access.

[0283] In addition, the UE also creates a pair of NAS counters for the first NAS connection corresponding to the first 3GPP access and sets them to initial values.

[0284] Furthermore, in one possible design, the UE generates a first key, namely K according to the AMF key, the third access type identifier and the identifier of the first 3GPP access. gNB 1. A first RRC key and a first user plane key can be further generated based on the first key. The method for AMF and UE to generate the first key is the same, which is not repeated here.

[0285] It is understandable that the present application does not limit the order of S702, S703 and S704.

[0286] Therefore, when RAN1 communicates with the UE, RAN1 and the UE may use the first RRC key to protect the first RRC signaling, and use the first user plane key to protect the first data.

[0287] S705: The UE sends a second registration request message to the AMF. In response, the AMF receives the second registration request message.

[0288] The second registration request message is used to request the UE to register with the network via the second 3GPP access. Optionally, the second registration request message may also include indication information. In addition, for other contents of the second registration request message, please refer to S505.

[0289] S706: The AMF generates a second key according to the third access type identifier and the second 3GPP access identifier.

[0290] In one possible implementation, after the AMF successfully authenticates the UE and before generating the second key, the AMF determines the second 3GPP identifier for the second 3GPP access. Specific implementations may include but are not limited to the following:

[0291] Method a: If the UE's security context includes the first field, the AMF determines that the UE is connected to the network through two 3GPP accesses based on the first field in the UE's security context, or if the second registration request message includes indication information, the AMF determines that the UE is connected to the network through two 3GPP accesses based on the indication information, and further the AMF may allocate a second 3GPP access identifier for the second 3GPP access. At this time, the AMF also needs to send the identifier of the second 3GPP access to the UE. For example, the AMF sends a second registration acceptance message to the UE, and the second registration acceptance message includes the identifier of the second 3GPP access. Or the AMF sends the identifier of the second 3GPP access to RAN2, and RAN2 carries the identifier of the second 3GPP access through the second AS security mode command to notify the UE.

[0292] Method b: If the AMF obtains the identifier of the unallocated 3GPP access based on the security context of the UE, and further determines that the UE is connected to the network through two 3GPP accesses, the AMF further uses the identifier of the unallocated 3GPP access as the identifier of the second 3GPP. At this time, the AMF also needs to send the identifier of the second 3GPP access to the UE. For example, the AMF sends a second registration acceptance message to the UE, and the second registration acceptance message includes the identifier of the second 3GPP access. Or the AMF sends the identifier of the second 3GPP access to RAN2, and RAN2 carries the identifier of the second 3GPP access through the second AS security mode command to notify the UE.

[0293] Method c: The second Registration Request message includes the identifier of the second 3GPP access, i.e., the identifier of the second 3GPP access allocated by the UE. In this case, the AMF determines that the UE is connected to the network via two 3GPP accesses and determines the identifier of the second 3GPP access based on the identifier of the second 3GPP access in the second Registration Request message.

[0294] In addition, the AMF saves the identifier of the second 3GPP access to the UE context. The AMF also creates a pair of NAS counters for the first NAS connection corresponding to the second 3GPP access and sets them to initial values.

[0295] It can be understood that the AMF maintains a set of UE security contexts for the first 3GPP access and the second 3GPP access. The UE security context includes two sets of NAS connection parameters. The parameters of the first NAS connection include the identifier of the first 3GPP access, the third access type identifier and a pair of NAS counters. The parameters of the second NAS connection include the identifier of the second 3GPP access, the third access type identifier and a pair of NAS counters.

[0296] For example, AMF sends the AMF key (e.g., K AMF ), the third access type identifier and the second 3GPP access identifier generate a second key. Among them, the third access type identifier is the access type identifier for identifying 3GPP access shown in Table 1. Combined with Table 1, it can be seen that the access type identifier here can be 0x01, and the second key can be recorded as K gNB 2.

[0297] In one example, the identifier of the second 3GPP access is used as the identifier for generating K gNB 2, then K gNB2 =KDF(FC, P0, L0, P1, L1, P2, L2), P0=the uplink NAS counter value corresponding to the second 3GPP access, L0=the length of the uplink NAS counter value corresponding to the second 3GPP access, P1=the third access type identifier, L1=the length of the third access type identifier, P2 is the identifier of the second 3GPP access, and L2 is the length of the second 3GPP access identifier.

[0298] In another example, the definition of P1 is updated, and P1 is determined according to the second 3GPP access identifier and the third access type identifier. For example, the result of connecting the second 3GPP access identifier and the third access type identifier is used as P1, then K gNB 2=KDF(FC, P0, L0, P1, L1), P0=the uplink NAS counter value corresponding to the second 3GPP access, L0=the length of the uplink NAS counter value corresponding to the second 3GPP access, P1=the third access type identifier||the identifier of the second 3GPP access, L1=the third access type identifier||the length of the identifier of the second 3GPP access.

[0299] In another example, the definition of P1 is updated, and P1 is determined according to the identifier of the second 3GPP access. For example, the identifier of the second 3GPP access is used as P1, then K gNB 2=KDF(FC, P0, L0, P1, L1), P0=the uplink NAS counter value corresponding to the second 3GPP access, L0=the length of the uplink NAS counter value corresponding to the second 3GPP access, P1=the identifier of the second 3GPP access, and L1=the length of the identifier of the second 3GPP access.

[0300] It will be understood that the above examples are only examples and are not intended to limit the present application. K can be generated by taking the uplink NAS counter value corresponding to the second 3GPP access, the length of the uplink NAS counter value corresponding to the second 3GPP access, the identifier of the second 3GPP access, the length of the identifier of the second 3GPP access, the third access type identifier, and one or more parameters of the length of the third access type identifier. gNB 2.

[0301] S707: The AMF sends the second key to RAN2. In response, RAN2 receives the second key from the AMF.

[0302] For example, RAN2 may use the received second key (eg, K gNB 2) Generate a second RRC key and a second user plane key. For example, the second RRC key includes K RRCenc 2 and K RRCint 2. The second user plane key includes K UPenc 2 and K UPint 2.

[0303] Optionally, the AMF may also send a second access type identifier to RAN2. In addition, RAN2 may also send a second AS security mode command to the UE. The second AS security mode command is used to notify the UE of the RRC signaling protection cipher algorithm and / or user plane protection cipher algorithm selected by the network side. Optionally, the second AS security mode command may also include the second access type identifier. Furthermore, after the UE executes S708 to generate the second key, the UE may also send a second AS security mode response to RAN2.

[0304] S708: The UE generates a second key according to the third access type identifier and the second 3GPP access identifier.

[0305] In a possible implementation manner, before generating the second key, the UE determines the identifier of the second 3GPP access.

[0306] In one example, the UE knows that it is connected to the network via two 3GPP accesses, and the second 3GPP access is a second 3GPP access. Then, before generating the second key, the UE determines the second 3GPP identifier for the second 3GPP access. For example, the UE can allocate the second 3GPP identifier itself.

[0307] In another example, the UE receives a second registration accept message from the AMF, where the second registration accept message includes an identifier of the second 3GPP access.

[0308] In yet another example, the UE receives a second AS security mode command from RAN2, where the second AS security mode command includes an identifier of a second 3GPP access.

[0309] The UE also creates a pair of NAS counters for the second NAS connection corresponding to the second 3GPP access and sets them to initial values.

[0310] It can be understood that the UE maintains a set of UE security contexts for the first 3GPP access and the second 3GPP access, and the UE security context includes two sets of NAS connection parameters. The parameters of the first NAS connection include the identifier of the first 3GPP access, the third access type identifier and a pair of NAS counters, and the parameters of the second NAS connection include the identifier of the second 3GPP access, the third access type identifier and a pair of NAS counters.

[0311] Furthermore, the UE generates a second key, namely K according to the AMF key, the third access type identifier and the second 3GPP access identifier. gNB 2. A second RRC key and a second user plane key can be further generated based on the second key. The method for AMF and UE to generate the second key is the same, which is not repeated here.

[0312] It is understandable that this application does not limit the order of S706, S707 and S708.

[0313] Therefore, when RAN2 communicates with the UE, RAN2 and the UE may use the second RRC key to protect the second RRC signaling, and use the second user plane key to protect the second data.

[0314] By adopting the above method, by allocating new identifiers for different 3GPP accesses during two 3GPP access processes, it is possible to ensure that the first key is different from the second key, thereby achieving key isolation.

[0315] In addition, in a possible implementation, the AMF uses a NAS security protection key and a first bearer parameter to perform security protection on the first NAS signaling, where the first NAS signaling corresponds to the first 3GPP access, and uses a security protection NAS key and a second bearer parameter to perform security protection on the second NAS signaling, where the second NAS signaling corresponds to the second 3GPP access. The first bearer parameter corresponds to the identifier of the first 3GPP access, which can be understood as the first bearer parameter being determined based on the identifier of the first 3GPP access, for example, the first bearer parameter being the identifier of the first 3GPP access or being determined based on the identifier of the first 3GPP access and the third access type identifier. The second bearer parameter corresponds to the identifier of the second 3GPP access, which can be understood as the second bearer parameter being determined based on the identifier of the second 3GPP access, for example, the second bearer parameter being the identifier of the second 3GPP access or being determined based on the identifier of the second 3GPP access and the third access type identifier.

[0316] For example, AMF is calculated based on K AMF Derive NAS confidentiality key K NASenc , NAS integrity protection key K NASint , according to the NAS confidentiality key K NASenc The first NAS signaling is protected confidentially using the first bearer parameter and the NAS integrity protection key K NASint and the first bearer parameter to perform integrity protection on the first NAS signaling, and NASenc The second NAS signaling is protected confidentially using the second bearer parameter and the NAS integrity protection key K NASint The second NAS signaling is integrity protected using the second bearer parameter.

[0317] Therefore, by using different bearer parameters, the problem of key stream reuse caused by two 3GPPs using the same NAS key can be avoided.

[0318] Example 4:

[0319] S801: The UE sends a first registration request message to the AMF via RAN1. Correspondingly, the AMF receives the first registration request message.

[0320] For the specific content of S801, please refer to the above S501.

[0321] Optionally, the first registration request message includes indication information, wherein the indication information may refer to the relevant content in the above S505.

[0322] S802: The AMF generates a first key according to the first value of the uplink NAS counter.

[0323] Exemplarily, the AMF allocates a third access type identifier to the first NAS connection corresponding to the first 3GPP access, creates a pair of NAS counters, and sets them to initial values. The pair of NAS counters includes an uplink NAS counter and a downlink NAS counter. The AMF stores the parameters of the first NAS connection in the UE's security context. The parameters of the first NAS connection include the third access type identifier and the pair of NAS counters. The third access type identifier is the access type identifier for identifying a 3GPP access shown in Table 1. As can be seen from Table 1, the access type identifier here can be 0x01.

[0324] In one possible implementation, the AMF sends a AMF ) and the first value of the uplink NAS counter to generate a first key. The first key can be recorded as K gNB 1. It is understandable that the generation of the first key also requires the combination of other parameters, such as K gNB 1=KDF(FC, P0, L0, P1, L1), where P0=the first value of the uplink NAS counter, L0=the length of the first value of the uplink NAS counter, P1=the third access type identifier, and L1=the length of the third access type identifier. For details, please refer to the above related content and will not be repeated here.

[0325] In addition, the AMF may also send a first registration accept message to the UE through RAN1.

[0326] S803: The AMF sends the first key to RAN1. In response, RAN1 receives the first key from the AMF.

[0327] For example, RAN1 may receive the first key (eg, K gNB 1) Generate a first RRC key and a first user plane key. For example, the first RRC key includes K RRCenc 1 and K RRCint 1. The first user plane key includes K UPenc 1 and K UPint 1.

[0328] In addition, RAN1 may also send an AS security mode command to the UE, where the AS security mode command is used to notify the UE of the RRC signaling protection key algorithm and / or user plane protection cipher algorithm selected by the network side. Further, after the UE executes S804 to generate the first key, the UE may also send an AS security mode response to RAN1.

[0329] S804: The UE generates a first key according to the first value of the uplink NAS counter.

[0330] Exemplarily, the UE further creates a pair of NAS counters for a first NAS connection corresponding to the first 3GPP access and sets the counters to initial values. The UE saves parameters of the first NAS connection, where the parameters of the first NAS connection include a third access type identifier and a pair of NAS counters. The pair of NAS counters includes an uplink NAS counter and a downlink NAS counter.

[0331] Furthermore, in a possible implementation, the UE generates a first key, namely K, based on the AMF key and the first value of the uplink NAS counter. gNB 1. A first RRC key and a first user plane key may be further generated based on the first key. The method for generating the first key by the AMF and the UE is the same and will not be repeated here.

[0332] It is understandable that the present application does not limit the order of S802, S803 and S804.

[0333] Therefore, when RAN1 communicates with the UE, RAN1 and the UE may use the first RRC key to protect the second RRC signaling, and use the first user plane key to protect the second data.

[0334] S805: The UE sends a second registration request message to the AMF. In response, the AMF receives the second registration request message.

[0335] The second registration request message is used to request the UE to register with the network through the second 3GPP access.

[0336] Optionally, the second registration request message includes indication information. In addition, for other contents of the second registration request message, reference may be made to S505.

[0337] S806: The AMF generates a second key according to the second value of the uplink NAS counter.

[0338] For example, the AMF does not create a new pair of NAS counters for the second NAS connection corresponding to the second 3GPP access, but uses the existing NAS counters. AMF ) and the second value of the uplink NAS counter to generate a second key. The second key can be recorded as K gNB 2. It is understandable that the generation of the second key also needs to be combined with other parameters, such as K gNB 2=KDF(FC, P0, L0, P1, L1), where P0=the second value of the uplink NAS counter, L0=the length of the second value of the uplink NAS counter, P1=the third access type identifier, and L1=the length of the third access type identifier.

[0339] In addition, the AMF may also send a second registration accept message to the UE through RAN2.

[0340] S807: The AMF sends the second key to RAN2. In response, RAN2 receives the second key from the AMF.

[0341] For example, RAN2 may use the received second key (eg, K gNB 2) Generate a second RRC key and a second user plane key. For example, the second RRC key includes K RRCenc 2 and K RRCint 2. The second user plane key includes K UPenc 2 and K UPint 2.

[0342] In addition, RAN2 may also send an AS security mode command to the UE, where the AS security mode command is used to notify the UE of the RRC signaling protection cipher algorithm and / or user plane protection cipher algorithm selected by the network side. Further, after the UE executes S808 to generate the second key, the UE may also send an AS security mode response to RAN2.

[0343] S808: The UE generates a second key according to the second value of the uplink NAS counter.

[0344] For example, the UE does not create a new pair of NAS counters for the second NAS connection corresponding to the second 3GPP access, but uses the existing NAS counters. AMF ) and the second value of the uplink NAS counter to generate a second key, namely K gNB 2. A second RRC key and a second user plane key may be further generated based on the second key. The AMF and the UE generate the second key in the same manner.

[0345] It is understandable that the present application does not limit the order of S806, S807 and S808.

[0346] Therefore, when RAN2 communicates with the UE, RAN2 and the UE may use the second RRC key to protect the second RRC signaling, and use the second user plane key to protect the second data.

[0347] By adopting the above method, by using different values ​​of the same uplink NAS counter in two 3GPP access processes, it is possible to ensure that the first key and the second key are different, thereby achieving key isolation.

[0348] In addition, after generating the second key, the AMF and the UE may also create a new pair of NAS counters for the second NAS connection corresponding to the second 3GPP access and set them to initial values. Using two sets of NAS counters allows the AMF to better distinguish between messages from RAN1 and RAN2, and to better confirm the order of messages from RAN1 and RAN2.

[0349] It is understood that, in order to implement the functions in the above embodiments, the terminal device or access and mobility management network element includes hardware structures and / or software modules corresponding to the execution of each function. Those skilled in the art should readily appreciate that, in combination with the units and method steps of the various examples described in the embodiments disclosed in this application, this application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a function is executed in hardware or in a manner driven by computer software depends on the specific application scenario and design constraints of the technical solution.

[0350] Figures 9 and 10 are schematic diagrams of possible communication devices provided in embodiments of the present application. These communication devices can be used to implement the functions of the terminal device or access and mobility management network element in the above method embodiments, thereby also achieving the beneficial effects of the above method embodiments.

[0351] As shown in Figure 9, the communication device 900 includes a processing unit 910 and a transceiver unit 920. The communication device 900 is used to implement the functions of the terminal device or access and mobility management network element in the method embodiments shown in Figures 5, 6, 7, and 8 above.

[0352] When the communication device 900 is used to implement the functions of the access and mobility management network element in the method embodiments shown in FIG5 , FIG6 , FIG7 , and FIG8 :

[0353] The transceiver unit 920 is used to receive a first registration request message from a terminal device, where the first registration request message is used to request the terminal device to register to a network through a first Third Generation Partnership Project 3GPP access; the processing unit 910 is used to generate a first key, where the first key is a key used for communication between the terminal device and the first access network device; the first access network device is used for the first 3GPP access; the transceiver unit 920 is used to send the first key to the first access network device; and receive a second registration request message from the terminal device, where the second registration request message is used to request the terminal device to register to a network through a second 3GPP access; the processing unit 910 is used to generate a second key, where the second key is a key used for communication between the terminal device and the second access network device, where the second access network device is used for the second 3GPP access; the first key is different from the second key; the transceiver unit 920 is used to send the second key to the second access network device.

[0354] In one possible design, the first registration request message and / or the second registration request message includes indication information, where the indication information is used to indicate that the terminal device is connected to the network via two 3GPP accesses.

[0355] In one possible design, the processing unit 910 is used to generate the first key according to the first access type identifier corresponding to the first 3GPP access when generating the first key; and to generate the second key according to the second access type identifier corresponding to the second 3GPP access when generating the second key, and the first access type identifier and the second access type identifier are different.

[0356] In one possible design, the second registration request message includes the indication information; the processing unit 910 is used to determine the second access type identifier for the second 3GPP access according to the indication information before generating the second key.

[0357] In one possible design, the first registration request message includes the indication information; the processing unit 910 is used to determine the first access type identifier for the first 3GPP access according to the indication information before generating the first key, and the first access type identifier is one of the dual 3GPP access type identifiers; before generating the second key, determine the second access type identifier for the second 3GPP access, and the second access type identifier is the other of the dual 3GPP access type identifiers.

[0358] In one possible design, the second access type identifier is an unused one of the dual 3GPP access type identifiers.

[0359] In one possible design, the transceiver unit 920 is used to send a first registration acceptance message to the terminal device, where the first registration acceptance message includes the first access type identifier; and / or send a second registration acceptance message to the terminal device, where the first registration acceptance message includes the second access type identifier.

[0360] In one possible design, the first bearer parameter includes the first access type identifier, and the second bearer parameter includes the second access type identifier; the processing unit 910 is configured to use the NAS security protection key and the first bearer parameter to securely protect the first NAS signaling, where the first NAS signaling corresponds to the first 3GPP access; and use the NAS security protection key and the second bearer parameter to securely protect the second NAS signaling, where the second NAS signaling corresponds to the second 3GPP access.

[0361] In one possible design, the processing unit 910 is used to generate the first key according to the third access type identifier and the identifier of the first 3GPP access when generating the first key, and the third access type identifier indicates that the access type is 3GPP access; when generating the second key, generate the second key according to the third access type identifier and the identifier of the second 3GPP access; the identifier of the first 3GPP access is different from the identifier of the second 3GPP access.

[0362] In one possible design, the first registration request message includes the indication information; the processing unit 910 is used to determine the identifier of the first 3GPP access for the first 3GPP access according to the indication information before generating the first key; and determine the identifier of the second 3GPP access for the second 3GPP access before generating the second key.

[0363] In one possible design, the transceiver unit 920 is used to obtain two 3GPP access identifiers from the data management network element according to the indication information when determining the identifier of the first 3GPP access for the first 3GPP access according to the indication information; use one of the two 3GPP access identifiers as the identifier of the first 3GPP access; and use the other of the two 3GPP access identifiers as the identifier of the second 3GPP access when determining the identifier of the second 3GPP access for the second 3GPP access.

[0364] In one possible design, the transceiver unit 920 is used to send a first registration acceptance message to the terminal device, where the first registration acceptance message includes the identifier of the first 3GPP access; and send a second registration acceptance message to the terminal device, where the second registration acceptance message includes the identifier of the second 3GPP access.

[0365] In one possible design, the first registration request message includes an identifier of the first 3GPP access, and the second registration request message includes an identifier of the second 3GPP access.

[0366] In one possible design, the first bearer parameter corresponds to the identifier of the first 3GPP access, and the second bearer parameter corresponds to the identifier of the second 3GPP access; the processing unit 910 is configured to use the NAS security protection key and the first bearer parameter to securely protect the first NAS signaling, where the first NAS signaling corresponds to the first 3GPP access; and use the NAS security protection key and the second bearer parameter to securely protect the second NAS signaling, where the second NAS signaling corresponds to the second 3GPP access.

[0367] In one possible design, the processing unit 910 is configured to, when generating a first key, generate the first key according to a first value of an uplink NAS counter; and, when generating a second key, generate the second key according to a second value of the uplink NAS counter; wherein the first 3GPP access and the second 3GPP access share the uplink NAS counter, and the first value is different from the second value.

[0368] When the communication device 900 is used to implement the functions of the terminal device in the method embodiments shown in FIG5 , FIG6 , FIG7 , and FIG8 :

[0369] The transceiver unit 920 is used to send a first registration request message to the access and mobility management network element, where the first registration request message is used to request the terminal device to register with the network through the first 3GPP access; the processing unit 910 is used to generate a first key, where the first key is the key used for communication between the terminal device and the first access network device; the first access network device is used for the first 3GPP access; the transceiver unit 920 is used to send a second registration request message to the access and mobility management network element, where the second registration request message is used to request the terminal device to register with the network through the second 3GPP access; the processing unit 910 is used to generate a second key, where the second key is the key used for communication between the terminal device and the second access network device, where the second access network device is used for the second 3GPP access; the first key is different from the second key.

[0370] In one possible design, the first registration request message and / or the second registration request message includes indication information, where the indication information is used to indicate that the terminal device is connected to the network through two 3GPP accesses;

[0371] In one possible design, the processing unit 910 is used to generate the first key according to the first access type identifier corresponding to the first 3GPP access when generating the first key; and to generate the second key according to the second access type identifier corresponding to the second 3GPP access when generating the second key, and the first access type identifier and the second access type identifier are different.

[0372] In one possible design, the processing unit 910 is used to determine the first access type identifier for the first 3GPP access before generating the first key, where the first access type identifier is one of the dual 3GPP access type identifiers; and before generating the second key, determine the second access type identifier for the second 3GPP access, where the second access type identifier is the other of the dual 3GPP access type identifiers.

[0373] In one possible design, the second access type identifier is an unused one of the dual 3GPP access type identifiers.

[0374] In one possible design, the transceiver unit 920 is used to receive a first registration acceptance message from the access and mobility management network element, where the first registration acceptance message includes the first access type identifier; and / or receive a second registration acceptance message from the access and mobility management network element, where the first registration acceptance message includes the second access type identifier.

[0375] In one possible design, the transceiver unit 920 is used to receive a first AS security mode command from the first access network device, the first AS security mode command including the first access type identifier; and / or, to receive a second AS security mode command from the second access network device, the second AS security mode command including the second access type identifier.

[0376] In one possible design, the first bearer parameter includes the first access type identifier, and the second bearer parameter includes the second access type identifier; the processing unit 910 is configured to use the NAS security protection key and the first bearer parameter to securely protect the first NAS signaling, where the first NAS signaling corresponds to the first 3GPP access; and use the NAS security protection key and the second bearer parameter to securely protect the second NAS signaling, where the second NAS signaling corresponds to the second 3GPP access.

[0377] In one possible design, the processing unit 910 is used to generate the first key according to the third access type identifier and the identifier of the first 3GPP access when generating the first key, and the third access type identifier indicates that the access type is 3GPP access; when generating the second key, generate the second key according to the third access type identifier and the identifier of the second 3GPP access; the identifier of the first 3GPP access is different from the identifier of the second 3GPP access.

[0378] In one possible design, the processing unit 910 is used to determine the identifier of the first 3GPP access for the first 3GPP access before generating the first key; and to determine the identifier of the second 3GPP access for the second 3GPP access before generating the second key.

[0379] In one possible design, the transceiver unit 920 is used to receive a first registration acceptance message from the access and mobility management network element, where the first registration acceptance message includes the identifier of the first 3GPP access; and receive and send a second registration acceptance message from the access and mobility management network element, where the second registration acceptance message includes the identifier of the second 3GPP access.

[0380] In one possible design, the transceiver unit 920 is used to receive a first AS security mode command from the first access network device, the first AS security mode command including the identifier of the first 3GPP access; and / or, to receive a second AS security mode command from the second access network device, the second AS security mode command including the identifier of the second 3GPP access.

[0381] In one possible design, the first registration request message includes an identifier of the first 3GPP access, and the second registration request message includes an identifier of the second 3GPP access.

[0382] In one possible design, the first bearer parameter corresponds to the identifier of the first 3GPP access, and the second bearer parameter corresponds to the identifier of the second 3GPP access; the processing unit 910 is configured to use the NAS security protection key and the first bearer parameter to securely protect the first NAS signaling, where the first NAS signaling corresponds to the first 3GPP access; and use the NAS security protection key and the second bearer parameter to securely protect the second NAS signaling, where the second NAS signaling corresponds to the second 3GPP access.

[0383] In one possible design, the processing unit 910 is configured to, when generating a first key, generate the first key according to a first value of an uplink NAS counter; and, when generating a second key, generate the second key according to a second value of the uplink NAS counter; wherein the first 3GPP access and the second 3GPP access share the uplink NAS counter, and the first value is different from the second value.

[0384] A more detailed description of the processing unit 910 and the transceiver unit 920 can be directly obtained by referring to the relevant descriptions in the method embodiments shown in Figures 5, 6, 7, and 8, and will not be repeated here.

[0385] As shown in Figure 10, communication device 1000 includes a processor 1010 and an interface circuit 1020. Processor 1010 and interface circuit 1020 are coupled to each other. It will be appreciated that interface circuit 1020 may be a transceiver or an input / output interface. Optionally, communication device 1000 may further include a memory 1030 for storing instructions executed by processor 1010, input data required by processor 1010 to execute instructions, or data generated by processor 1010 after executing instructions.

[0386] When the communication device 1000 is used to implement the methods shown in Figures 5, 6, 7, and 8, the processor 1010 is used to implement the functions of the above-mentioned processing unit 910, and the interface circuit 1020 is used to implement the functions of the above-mentioned transceiver unit 920.

[0387] It is understood that the processor in the embodiments of the present application may be a central processing unit (CPU) 910, or may be another general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. The general-purpose processor may be a microprocessor or any conventional processor.

[0388] The present application provides another example of a device, which includes at least one processor and at least one memory, the at least one processor and the at least one memory being coupled, the at least one memory being used to store instructions. When the instructions are executed by the at least one processor, the communication device executes the method in the above embodiment. Taking the communication device including a processor and a memory as an example, as shown in FIG10 , the communication device 1000 includes a processor 1010 and a memory 1030. The processor 1010 and the memory 1030 are coupled, and the memory 1030 stores instructions. When the instructions stored in the memory 1030 are executed by the processor 1010, the communication device 1000 executes the method executed by the terminal device or the access and mobility management network element in the above embodiment.

[0389] The method steps in the embodiments of the present application can be implemented in hardware or in software instructions that can be executed by a processor. The software instructions can be composed of corresponding software modules, and the software modules can be stored in random access memory, flash memory, read-only memory, programmable read-only memory, erasable programmable read-only memory, electrically erasable programmable read-only memory, registers, hard disk, mobile hard disk, CD-ROM or any other form of storage medium well known in the art. An exemplary storage medium is coupled to the processor so that the processor can read information from the storage medium and write information to the storage medium. The storage medium can also be an integral part of the processor. The processor and the storage medium can be located in an ASIC. In addition, the ASIC can be located in a terminal device or an access and mobility management network element. The processor and the storage medium can also exist as discrete components in a terminal device or an access and mobility management network element.

[0390] In the above embodiments, all or part of the embodiments may be implemented using software, hardware, firmware, or any combination thereof. When implemented using software, all or part of the embodiments may be implemented in the form of a computer program product. The computer program product includes one or more computer programs or instructions. When the computer program or instructions are loaded and executed on a computer, the processes or functions described in the embodiments of the present application are performed in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, a network device, a user device, or other programmable device. The computer program or instructions may be stored in a computer-readable storage medium or transferred from one computer-readable storage medium to another. For example, the computer program or instructions may be transferred from one website, computer, server, or data center to another website, computer, server, or data center via wired or wireless means. The computer-readable storage medium may be any available medium that can be accessed by a computer or a data storage device such as a server or data center that integrates one or more available media. The available medium may be a magnetic medium, such as a floppy disk, hard disk, or magnetic tape; an optical medium, such as a digital video disk; or a semiconductor medium, such as a solid-state drive. The computer-readable storage medium may be a volatile or nonvolatile storage medium, or may include both volatile and nonvolatile types of storage media.

[0391] In the various embodiments of the present application, unless otherwise specified or there is a logical conflict, the terms and / or descriptions between different embodiments are consistent and can be referenced by each other. The technical features in different embodiments can be combined to form new embodiments according to their inherent logical relationships.

[0392] In this application, "at least one" means one or more, and "more" means two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural. In the text description of this application, the character " / " generally indicates that the previous and next associated objects are in an "or" relationship; in the formula of this application, the character " / " indicates that the previous and next associated objects are in a "division" relationship. "Including at least one of A, B and C" can mean: including A; including B; including C; including A and B; including A and C; including B and C; including A, B and C.

[0393] It is understood that the various numbers used in the embodiments of this application are merely for ease of description and are not intended to limit the scope of the embodiments of this application. The order of the sequence numbers of the above-mentioned processes does not necessarily imply a specific order of execution; the order of execution of the processes should be determined by their functions and inherent logic.< / guami>

Claims

1. A key derivation method, characterized in that: The method includes: Receiving a first registration request message from a terminal device, where the first registration request message is used to request the terminal device to register with a network through a first Third Generation Partnership Project 3GPP access; Generate a first key, where the first key is a key used for communication between the terminal device and the first access network device; the first access network device is used for the first 3GPP access; Sending the first key to the first access network device; receiving a second registration request message from the terminal device, where the second registration request message is used to request the terminal device to register with a network through a second 3GPP access; generating a second key, where the second key is a key used for communication between the terminal device and the second access network device, and the second access network device is used for the second 3GPP access; the first key is different from the second key; Send the second key to the second access network device.

2. The method according to claim 1, characterized in that The first registration request message and / or the second registration request message includes indication information, and the indication information is used to indicate that the terminal device is connected to the network via two 3GPP accesses.

3. The method according to claim 1 or 2, characterized in that Generate a first key, including: generating the first key according to a first access type identifier corresponding to the first 3GPP access; Generate a second key, including: The second key is generated according to a second access type identifier corresponding to the second 3GPP access, where the first access type identifier is different from the second access type identifier.

4. The method according to claim 3, characterized in that The second registration request message includes the indication information; Before generating the second key, the method further includes: Determine the second access type identifier for the second 3GPP access according to the indication information.

5. The method according to claim 3, characterized in that The first registration request message includes the indication information; Before generating the first key, it also includes: Determine the first access type identifier for the first 3GPP access according to the indication information, where the first access type identifier is one of dual 3GPP access type identifiers; Before generating the second key, the method further includes: The second access type identifier is determined for the second 3GPP access, where the second access type identifier is the other of the dual 3GPP access type identifiers.

6. The method according to claim 5, characterized in that The second access type identifier is an unused one of the dual 3GPP access type identifiers.

7. The method according to any one of claims 3 to 6, characterized in that: Also includes: Sending a first registration acceptance message to the terminal device, where the first registration acceptance message includes the first access type identifier; And / or, sending a second registration acceptance message to the terminal device, wherein the second registration acceptance message includes the second access type identifier.

8. The method according to any one of claims 3 to 7, characterized in that: The first bearer parameter includes the first access type identifier, and the second bearer parameter includes the second access type identifier; The method further comprises: Performing security protection on a first NAS signaling using a non-access layer NAS security protection key and the first bearer parameter, the first NAS signaling corresponding to the first 3GPP access; The second NAS signaling is securely protected using the NAS security protection key and the second bearer parameter, where the second NAS signaling corresponds to the second 3GPP access.

9. The method according to claim 1 or 2, characterized in that: Generate a first key, including: generating the first key according to a third access type identifier and the first 3GPP access identifier, wherein the third access type identifier indicates that the access type is 3GPP access; Generate a second key, including: The second key is generated according to the third access type identifier and the identifier of the second 3GPP access; the identifier of the first 3GPP access is different from the identifier of the second 3GPP access.

10. The method according to claim 9, characterized in that The first registration request message includes the indication information; Before generating the first key, it also includes: determining an identifier of the first 3GPP access for the first 3GPP access according to the indication information; Before generating the second key, the method further includes: An identifier of the second 3GPP access is determined for the second 3GPP access.

11. The method according to claim 10, characterized in that Determining an identifier of the first 3GPP access for the first 3GPP access according to the indication information includes: Acquire two 3GPP access identifiers from the data management network element according to the indication information; Using one of the two 3GPP access identifiers as the identifier of the first 3GPP access; Determining an identifier of the second 3GPP access for the second 3GPP access includes: The other of the two 3GPP access identifiers is used as the identifier of the second 3GPP access.

12. The method according to any one of claims 9 to 11, characterized in that: Also includes: Sending a first registration acceptance message to the terminal device, where the first registration acceptance message includes an identifier of the first 3GPP access; A second registration acceptance message is sent to the terminal device, where the second registration acceptance message includes an identifier of the second 3GPP access.

13. The method according to claim 9, characterized in that The first registration request message includes the identifier of the first 3GPP access, and the second registration request message includes the identifier of the second 3GPP access.

14. The method according to any one of claims 9 to 13, characterized in that: The first bearer parameter corresponds to the identifier of the first 3GPP access, and the second bearer parameter corresponds to the identifier of the second 3GPP access; The method further comprises: Performing security protection on a first NAS signaling using a NAS security protection key and the first bearer parameter, the first NAS signaling corresponding to the first 3GPP access; The second NAS signaling is securely protected using the NAS security protection key and the second bearer parameter, where the second NAS signaling corresponds to the second 3GPP access.

15. The method according to claim 1 or 2, characterized in that: Generate a first key, including: Generate the first key according to the first value of the uplink NAS counter; Generate a second key, including: The second key is generated according to a second value of the uplink NAS counter; wherein the first 3GPP access and the second 3GPP access share the uplink NAS counter, and the first value is different from the second value.

16. A key derivation method, characterized in that: The method includes: Sending a first registration request message to an access and mobility management network element, where the first registration request message is used to request a terminal device to register with a network through a first 3GPP access; Generate a first key, where the first key is a key used for communication between the terminal device and the first access network device; the first access network device is used for the first 3GPP access; Sending a second registration request message to the access and mobility management network element, where the second registration request message is used to request the terminal device to register with the network through a second 3GPP access; Generate a second key, where the second key is a key used for communication between the terminal device and the second access network device, and the second access network device is used for the second 3GPP access; the first key is different from the second key.

17. The method according to claim 16, characterized in that The first registration request message and / or the second registration request message includes indication information, and the indication information is used to indicate that the terminal device is connected to the network via two 3GPP accesses.

18. The method according to claim 16 or 17, characterized in that Generate a first key, including: generating the first key according to a first access type identifier corresponding to the first 3GPP access; Generate a second key, including: The second key is generated according to a second access type identifier corresponding to the second 3GPP access, where the first access type identifier is different from the second access type identifier.

19. The method according to claim 18, characterized in that Before generating the first key, it also includes: Determine the first access type identifier for the first 3GPP access, where the first access type identifier is one of dual 3GPP access type identifiers; Before generating the second key, the method further includes: The second access type identifier is determined for the second 3GPP access, where the second access type identifier is the other of the dual 3GPP access type identifiers.

20. The method of claim 19, wherein: The second access type identifier is an unused one of the dual 3GPP access type identifiers.

21. The method according to any one of claims 18 to 20, characterized in that: Also includes: receiving a first registration accept message from the access and mobility management network element, wherein the first registration accept message includes the first access type identifier; and / or, receiving a second registration acceptance message from the access and mobility management network element, wherein the first registration acceptance message includes the second access type identifier; Alternatively, a first access layer AS security mode command is received from the first access network device, the first AS security mode command including the first access type identifier; and / or a second AS security mode command is received from the second access network device, the second AS security mode command including the second access type identifier.

22. The method according to any one of claims 18 to 21, characterized in that: The first bearer parameter includes the first access type identifier, and the second bearer parameter includes the second access type identifier; The method further comprises: Performing security protection on a first NAS signaling using the NAS security protection key and the first bearer parameter, where the first NAS signaling corresponds to the first 3GPP access; The second NAS signaling is securely protected using the NAS security protection key and the second bearer parameter, where the second NAS signaling corresponds to the second 3GPP access.

23. The method according to claim 16 or 17, characterized in that Generate a first key, including: generating the first key according to a third access type identifier and the first 3GPP access identifier, wherein the third access type identifier indicates that the access type is 3GPP access; Generate a second key, including: The second key is generated according to the third access type identifier and the identifier of the second 3GPP access; the identifier of the first 3GPP access is different from the identifier of the second 3GPP access.

24. The method of claim 23, wherein: Before generating the first key, it also includes: determining an identifier of the first 3GPP access for the first 3GPP access; Before generating the second key, the method further includes: An identifier of the second 3GPP access is determined for the second 3GPP access.

25. The method according to claim 23 or 24, characterized in that Also includes: receiving a first registration accept message from the access and mobility management network element, wherein the first registration accept message includes an identifier of the first 3GPP access; and / or, receiving and sending a second registration acceptance message from the access and mobility management network element, where the second registration acceptance message includes an identifier of the second 3GPP access; Alternatively, receiving a first AS security mode command from the first access network device, where the first AS security mode command includes an identifier of the first 3GPP access; And / or, receiving a second AS security mode command from the second access network device, where the second AS security mode command includes an identifier of the second 3GPP access.

26. The method according to claim 23 or 24, characterized in that The first registration request message includes the identifier of the first 3GPP access, and the second registration request message includes the identifier of the second 3GPP access.

27. The method according to any one of claims 23 to 26, characterized in that The first bearer parameter corresponds to the identifier of the first 3GPP access, and the second bearer parameter corresponds to the identifier of the second 3GPP access; The method further comprises: Performing security protection on a first NAS signaling using a NAS security protection key and the first bearer parameter, the first NAS signaling corresponding to the first 3GPP access; The second NAS signaling is securely protected using the NAS security protection key and the second bearer parameter, where the second NAS signaling corresponds to the second 3GPP access.

28. The method according to claim 16 or 17, characterized in that Generate a first key, including: Generate the first key according to the first value of the uplink NAS counter; Generate a second key, including: Generate the second key according to the second value of the uplink NAS counter; wherein the first 3GPP access and the second 3GPP access shares the uplink NAS counter, and the first value is different from the second value.

29. A communication device, characterized in that: The method comprises a unit or a module for executing the method according to any one of claims 1 to 15, or comprises a unit or a module for executing the method according to any one of claims 16 to 28.

30. A communication device, characterized in that: include: One or more processors and one or more memories; wherein the one or more memories store one or more programs, and when the programs are executed by the one or more processors, the device executes the method as described in any one of claims 1-15, or executes the method as described in any one of claims 16-28.

31. A chip system, characterized in that: The chip system includes at least one chip and a memory, and the at least one chip is used to read and execute a program stored in the memory to implement the method as described in any one of claims 1 to 15, or to implement the method as described in any one of claims 16 to 28.

32. A readable storage medium, characterized in that: The readable storage medium includes a program, and when the program is executed on a device, the device executes the method according to any one of claims 1 to 15, or executes the method according to any one of claims 16 to 28.

33. A communication system, characterized in that: The communication system comprises an access and mobility management network element, a first access network device and a second access network device, The access and mobility management network element is used to perform the method according to any one of claims 1 to 15, The first access network device is used to receive a first key; The second access network device is used to receive a second key.

34. The communication system according to claim 33, characterized in that The communication system further comprises a terminal device, wherein the terminal device is configured to execute the method according to any one of claims 16 to 28.

35. A computer program product, characterized in that The computer program product includes a program or an instruction, and when the program or the instruction is executed by a device, the device executes the method according to any one of claims 1 to 15, or executes the method according to any one of claims 16 to 28.

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