Cryptanalysis of Two Tripartite Authenticated Key Agreement Protocols

The tripartite authenticated key agreement (AKA) protocol is crucial in providing data confidentiality to subsequent communications among three parties over an insecure public network. In recent years, several identity-based and certificate less tripartite AKA protocols have been proposed. Unfortunately, most of them are insecure. In this paper, we analyze an identity-based tripartite AKA protocol and a certificate less tripartite AKA protocol. Our cryptanalysis shows that one neither meets the desirable security properties.