Deniable authentication on the internet

Abstract

Deniable authentication is a technique that allows one party to send messages to another while the latter can not prove to a third party the fact of communication. In this paper, we formalize a natural notion of deniable security and naturally extend the basic authenticator theorem by Bellare et al. [1] to the setting of deniable authentication. Of independent interest, this extension is achieved by defining a deniable MT-authenticator via a game. This game is essentially borrowed from the notion of universal composition [6] although we do not assume any result or background about it. Then we construct a 3-round deniable MT-authenticator. Finally, as our application, we obtain a key exchange protocol that is deniably secure in the real world. © 2008 Springer-Verlag Berlin Heidelberg.