Improvement of One Password-Based Authenticated Key Exchange Protocol

In 2006, Wu et al proposed a password-based authenticated key exchange protocol. It is considered much more from the practical perspective. There are three hash functions required. In this paper, we revisit and improve it. Our improvement only needs one hash function, without loss of any security. In contrast, the revisited protocol saves about 2/3 memories for the system parameters. The basic idea behind the improvement is that: a partial-preimage resistance one-way function should be as difficult to recover any substring as to recover the entire input.