A novel deniable authentication protocol using generalized ElGamal signature scheme

A deniable authentication protocol enables a receiver to identify the true source of a given message, but not to prove the identity of the sender to a third party. This property is very useful for providing secure negotiation over the Internet. Consequently, many interactive and non-interactive deniable authentication protocols have been proposed. However, the interactive manner makes deniable protocols inefficient. In addition, a security hole is generated in deniable protocols that use the non-interactive manner if a session secret is compromised. Thus, there is no secure and efficient deniable authentication protocol as of now. In this paper, a new protocol based on the non-interactive manner is proposed to efficiently and securely achieve deniable authentication. This protocol can furthermore replace the underlying signature scheme in order to retain a secure status even if the previously used signature method is broken.