Light-Weight Key Exchange with Different Passwords in the Standard Model

Jeong Ok Kwon (Samsung SDS, Korea)

Ik Rae Jeong (Korea University, Korea)

Dong Hoon Lee (Korea University, Korea)

Abstract: In this paper, we consider password-based authenticated key exchange with different passwords, where the users only share a password with the trusted server but do not share between themselves. The server helps the users share a cryptographically secure session key by using their different passwords. We propose a light-weight password-based authenticated key exchange protocol with different passwords, i.e., it requires only 2 rounds and 4 modular exponentiations per user. The protocol provides forward secrecy, known-key secrecy, key secrecy against the curious server, and security against undetectable online dictionary attacks without random oracles.

Keywords: different passwords, forward secrecy, key secrecy, password-based key exchange

Categories: C.2.0, D.4.6, E.3