Apparatus and method for transitioning enhanced security context from a utran-based serving network to a geran-based serving network

A remote station, comprising:

• means for generating first and second session keys, in accordance with a first security context, using a first information element and using a root key associated with the first security context;
• means for receiving a first message from a first-type serving network, wherein the first message includes a second information element signaling to the remote station to generate third and fourth session keys for use with a second-type serving network;
• means for generating, in response to the first message, the third and fourth session keys using the second information element and the first and second session keys;
• and
• means for protecting wireless communications, on the second-type serving network, based on the third and fourth session keys.

A remote station, comprising:

• a processor configured to:
• generate first and second session keys, in accordance with a first security context, using a first information element and using a root key associated with the first security context;
• receive a first message from a first-type serving network, wherein the first message includes a second information element signaling to the remote station to generate third and fourth session keys for use with a second-type serving network;
• generate, in response to the first message, the third and fourth session keys using the second information element and the first and second session keys;
• and
• protect wireless communications, on the second-type serving network, based on the third and fourth session keys.

A computer program product, comprising:

• computer-readable storage medium, comprising:
• code for causing a computer to generate first and second session keys, in accordance with a first security context, using a first information element and using a root key associated with the first security context;
• code for causing a computer to receive a first message from a first-type serving network, wherein the first message includes a second information element signaling to the remote station to generate third and fourth session keys for use with a second-type serving network;
• code for causing a computer to generate, in response to the first message, the third and fourth session keys using the second information element and the first and second session keys;
• and
• code for causing a computer to protect wireless communications, on the second-type serving network, based on the third and fourth session keys.