Method and apparatus for UE and application function session protection for model transfer

A user equipment (UE) comprising:

• at least one processor;
• and
• at least one memory storing instructions that, when executed by the at least one processor, cause the UE at least to perform:
• maintaining an authentication and key management for applications, AKMA, context including a UE identifier, an AKMA anchor key KAKMA, and a primary AKMA key identifier (A-KID), wherein the primary A-KID is in a Network Access Identifier (NAI) format that includes an AKMA temporary UE identifier (A-TID);
• receiving from an application function (AF) a secondary AKMA key identifier (A-KID′) in an application session establishment request received over an application-specific network application function interface (Ua*);
• validating the AF for the UE using the AKMA key identifier A-KID, the validating comprising:
• obtaining from the secondary AKMA key identifier A-KID′ an AKMA temporary UE identifier A-TID;
• and
• verifying whether the A-TID was included in the primary AKMA key identifier A-KID;
• and
• if the verifying is positive, then
• establishing an application session with the AF;
• and
• receiving an artificial intelligence, AI, model from the AF;
• or
• otherwise rejecting the application session with the AF,
• wherein the validating comprises obtaining a secondary AKMA key identifier A-KID′ from a non-access stratum (NAS) wherein the secondary AKMA key identifier A-KID′ includes an AF identifier that identifies the AF, wherein the secondary AKMA key identifier A-KID′ is obtained from a session establishment request sent by the AF to the UE;
• performing authentication and key management for applications (AKMA) based on 3GPP credentials in the 5G system (5GS);
• using an AKMA application key KAF derived from the AKMA anchor key (KAKMA), in encryption or decryption of data exchanged in the application session;
• and
• authenticating the UE to a home network operator and responsively obtaining the AKMA context prior to the maintaining of the AKMA context.