UMTS-AKA and EAP-AKA Inter-working for Fast Handovers in All-IP Networks

3GPP service architecture evolution (SAE) / long term evolution (LTE) activity sets the requirement of provisioning secure and seamless handover. In handover, however, key management (i.e., key derivation and key transfer) and mutual authentication form a significant source of latency. Together with the seamlessness requirement 3GPP also requires the reuse of universal subscriber identity module (USIM) and the existing authentication and key management procedure or Authentication and Key Agreement (AKA). In this paper we consider UMTS-AKA and extensible authentication protocol-AKA (EAP-AKA) as the two USIM- based authentication and key management protocols. We propose an architecture that can be used in SAE/LTE for efficient inter-working between UMTS-AKA and EAP-AKA during handover. Efficient inter-working here translates to avoiding signaling with the home domain during handover. Our focus is on the top-level key management aspect and we do not address derivation of child keys. Our solution speeds up handover signaling by one round trip time (RTT) to the home domain. We investigate also the relevance of key hierarchy solutions proposed in IETF for speeding up re-authentications.