Patent ID: 11343675

Abstract:
Disclosed is a method in an operator authentication server for authentication of a communication device associated with a communication device manager. The communication device manager being associated with a plurality of communication devices, wherein the operator authentication server has transmitted group subscriber identity module (SIM) information to the communication device manager, wherein the group SIM information is associated with an international mobile subscriber identity (IMSI) number and a shared secret K. The method comprises receiving from the communication device a request for authentication comprising a sub identifier associated with the communication device; determining whether the sub identifier is known. Wherein if it is determined that the sub identifier is known, the method comprises: deriving a secret Ki associated with the communication device based on the shared secret K, and the sub identifier; transmitting a challenge to the communication device, wherein the challenge is formed cryptographically based on the derived secret Ki; receiving from the communication device a response to the challenge, wherein the response is cryptographically formed based on the derived secret Ki; determining whether the received response is correct by confirming that it was cryptographically formed by using the derived secret Ki. When it is determined that the received response is correct, the method comprises: authenticating the communication device and derive a first session key based on the derived secret Ki.