## Cryptology ePrint Archive: Report 2006/302

Noninteractive two-channel message authentication based on hybrid-collision resistant hash functions.

Atefeh Mashatan and Douglas R. Stinson

Abstract: We consider the problem of non-interactive message authentication using two channels: an insecure broadband channel and an authenticated narrow-band channel. This problem has been considered in the context of ad hoc networks, where it is assumed that there is neither a secret key shared among the two parties, nor a public-key infrastructure in place. We present a formal model for protocols of this type, along with a new protocol which is as efficient as the best previous protocols. The security of our protocol is based on a new property of hash functions that we introduce, which we name hybrid-collision resistance''.

Category / Keywords: cryptographic protocols / message authentication, hybrid-collisions