Arbitrated unconditionally secure authentication can be unconditionally protected against arbiter’s attacks

Abstract

Given an arbiter whose arbitrage is trusted, an authentication scheme is presented which is unconditionally secure against impersonation and/or substitution attacks performed by the arbiter, whereas previous scheme did not protect against such attacks. Furthermore, the scheme protects unconditionally against: impersonation/substitution attacks done by an outsider, against disavowal of a message by the sender, and against the receiver forging a message which was never sent. A practical scheme based on finite geometry is presented. Adaptations of the scheme realize an asymmetric conventional authentication scheme, and the set-up of an unconditionally secure oblivious transfer system.