Patent ID: 8645695

Claim:
A multiple security context management method for use on a mobile equipment, said method comprising: responsive to receiving a first challenge from a first, packet-switched, network pursuant to a first security context requesting a removable subscriber identity module (SIM) for generating a first set of authentication vectors with respect to said first security context, receiving said first set of authentication vectors and storing said first set of authentication vectors in a first location on one of said mobile equipment and said subscriber identity module, said first location being associated with said first security context; responsive to receiving a second challenge from a second, circuit-switched, network pursuant to a second security context in order to receive circuit-switched services via said first network, requesting said removable subscriber identity module for generating a second set of authentication vectors with respect to said security context, receiving said second set of authentication vectors and storing said second set of authentication vectors in a second location on one of said mobile equipment and said subscriber identity module, said second location being associated with said second security context; and responsive to preparation for transferring access for said mobile equipment from said first network to said second network, receiving a security mode command message from a network node coupled to said second network and determining that said second set of authentication vectors should be used instead of said first set of authentication vectors for handover from said first network to said second network.