Homework SourseWhat is the purpose of AUTN field used in UMTS authenticatio
What is the purpose of AUTN field used in UMTS authentication? Do the MAC and AUTN authenticate the keys CK and IK? How is the freshness of CK and IK ensured?
What is the purpose of AUTN field used in UMTS authentication? Do the MAC and AUTN authenticate the keys CK and IK? How is the freshness of CK and IK ensured?
Solution
In an EPS authentication challenge, the UE shall check the authenticity of the core network by means of the AUTN parameter received in the AUTHENTICATION REQUEST message. This enables the UE to detect a false network. The UE shall send AUTHENTICATION FAILUREmessage to indicate the EPS authentication failure
MAC code failure: If the UE finds that the MAC code supplied by the core network in the AUTN parameter is invalid, then the UE shall send anAUTHENTICATION FAILURE message to the network, with the EMM cause #20 \"MAC failure\". The network may initiate an identification procedure to obtain the IMSI from the UE or may also decides to terminate the authentication procedure
