Anchor key generation method, device, and system
An anchor key generation method, device, and system, where the method includes generating, by a unified data management network element (UDM), an intermediate key based on a cipher key (CK), an integrity key (IK), and indication information regarding an operator; sending, by the UDM, the intermediate key to an authentication server function (AUSF); receiving, by the AUSF, the intermediate key; generating, by the AUSF, an anchor key based on the intermediate key; sending, by the AUSF, the anchor key to a security anchor function (SEAF); and generating, by the SEAF, a key (Kamf) based on the anchor key, where the Kamf is used to derive a 3 rd Generation Partnership Project (3GPP) key.
1. A method implemented by an apparatus in a communication system, the method comprising:
generating an intermediate key based on a cipher key (CK), an integrity key (IK), and an operator type identifier comprising a service network (SN) identifier;
generating an anchor key based on the intermediate key;
generating a key (K amf ) based on the anchor key;
deriving a base station key based on the K amf ; and
deriving, based on the base station key, a user plane cipher key for performing encryption protection on user plane data, a user plane integrity key for performing integrity protection on the user plane data, a control plane cipher key for performing encryption protection on control plane data, and a control plane integrity key for performing integrity protection on the control plane data,
wherein the intermediate key is shared between the apparatus and an authentication server of the communication system, the anchor key is shared between the apparatus and a security anchor of the communication system, and the K amf is shared between the apparatus and an access and mobility control function network element of the communication system.
2. The method according to claim 1 , wherein generating the anchor key based on the intermediate key comprises:
generating an extended master session key (EMSK′) based on the intermediate key;
generating a key (K left ) by truncating a bit of the EMSK′; and
obtaining the anchor key based on the K left and the SN identifier.
3. The method according to claim 1 , further comprising deriving a non-access stratum (NAS) key based on the K amf .
4. The method according to claim 1 , wherein the SN identifier is an SN name.
5. The method according to claim 1 , wherein the operator type identifier further comprises an access type identifier.
6. The method according to claim 5 , wherein the access type identifier indicates a generation of the communication system.
7. The method according to claim 1 , further comprising generating the CK and the 1K based on a root key.
8. An apparatus in a communication system and comprising:
a processor configured to execute instructions in a memory to cause the apparatus to:
generate an intermediate key based on a cipher key (CK), an integrity key (IK), and an operator type identifier comprising a service network (SN) identifier;
generate an anchor key based on the intermediate key;
generate a key (K amf ) based on the anchor key;
derive a base station key based on the K amf ; and
derive, based on the base station key, a user plane cipher key for performing encryption protection on user plane data, a user plane integrity key for performing integrity protection on the user plane data, a control plane cipher key for performing encryption protection on control plane data, and a control plane integrity key for performing integrity protection on the control plane data,
wherein the intermediate key is shared between the apparatus and an authentication server of the communication system, the anchor key is shared between the apparatus and a security anchor of the communication system, and the K amf is shared between the apparatus and an access and mobility control function network element of the communication system.
9. The apparatus according to claim 8 , wherein the processor is further configured to execute the instructions to cause the apparatus to generate the anchor key by:
generating an extended master session key (EMSK′) based on the intermediate key;
generating a key (K left ) by truncating a bit of the EMSK′; and
obtaining the anchor key based on the K left and the SN identifier.
10. The apparatus according to claim 8 , wherein the processor is further configured to execute the instructions to cause the apparatus to derive a non-access stratum (NAS) key based on the K amf .
11. The apparatus according to claim 8 , wherein the SN identifier is an SN name.
12. The apparatus according to claim 8 , wherein the operator type identifier further comprises an access type identifier.
13. The apparatus according to claim 12 , wherein the access type identifier indicates a generation of the communication system.
14. The apparatus according to claim 8 , wherein the processor is further configured to execute the instructions to cause the apparatus generate the CK and the IK based on a root key.
15. A non-transitory computer-readable storage medium configured to store instructions, which when executed by a processor of an apparatus in a communication system, cause the apparatus to:
generate an intermediate key based on a cipher key (CK), an integrity key (IK), and an operator type identifier comprising a service network (SN) identifier;
generate an anchor key based on the intermediate key;
generate a key (K amf ) based on the anchor key;
derive a base station key based on the K amf ; and
derive, based on the base station key, a user plane cipher key for performing encryption protection on user plane data, a user plane integrity key for performing integrity protection on the user plane data, a control plane cipher key for performing encryption protection on control plane data, and a control plane integrity key for performing integrity protection on the control plane data,
wherein the intermediate key is shared between the apparatus and an authentication server of the communication system, the anchor key is shared between the apparatus and a security anchor of the communication system, and the Kamf is shared between the apparatus and an access and mobility control function network element of the communication system.
16. The non-transitory computer-readable storage medium according to claim 15 , wherein the instructions, when executed by the processor, further cause the apparatus to generate the anchor key by:
generating an extended master session key (EMSK′) based on the intermediate key;
generating a key (Kleft) by truncating a bit of the EMSK′; and
obtaining the anchor key based on the Kleft and the SN identifier.
17. The non-transitory computer-readable storage medium according to claim 15 , wherein the operator type identifier further comprises an access type identifier, and wherein the access type identifier indicates a generation of the communication system.
18. The non-transitory computer-readable storage medium according to claim 15 , wherein the instructions, when executed by the processor, further cause the apparatus to generate the CK and the IK based on a root key.
19. The non-transitory computer-readable storage medium according to claim 15 , wherein the instructions, when executed by the processor, further cause the apparatus to derive a non-access stratum (NAS) key based on the K amf .
20. The non-transitory computer-readable storage medium according to claim 15 , wherein the SN identifier is an SN name.