Authenticated Key Transport Protocol Based on a Locking-Signing Technique

Key distribution is one of the fundamental issues in modern cryptography and its security is the main concern in World Wide Web-based applications. In this paper, a new type of secure key transport protocol with a no-key encryption, locking and signing technique is proposed based on Shamir´s and Khayat´s protocols. The basic security rests on the difficulty of the discrete logarithm problem and random numbers for challenge-response are utilized to detect replay and impersonation, providing mutual entity authentication and explicit key authentication. Compared with the Beller-Yacobi´s protocol, two parties sharing no a priori keying material can end up with a shared secret key without performing asymmetric encryption and it is immune to the man-in-the-middle attack. Analysis also shows that expensive cost of computing all the inverses of underlying group elements can be avoided by performing pre-computation, facilitating on-line key establishment.