A Security Enhancement and Proof for Authentication and Key Agreement (AKA)

Date Added: Jun 2010
Format: PDF

In this paper, the authors consider Authentication and Key Agreement (AKA), a popular client-server Key Exchange (KE) protocol, commonly used in wireless standards (e.g., UMTS), and widely considered for new applications. The authors discuss natural potential usage scenarios for AKA, attract attention to subtle vulnerabilities, propose a simple and efficient AKA enhancement, and provide its formal proof of security. The vulnerabilities arise due to the fact that AKA is not a secure KE in the standard cryptographic sense, since Client C does not contribute randomness to the session key.