Authenticated Key Exchange, Signcryption and Deniable Signcryption Protocols Based on Two Hard Problems

Arazi was the first author to propose the integration of a key exchange protocol with a digital signature algorithm. Other authors have subsequently proposed methods to increase the level of security and achieve the necessary properties of authenticated key exchange protocols. However, these proposals exhibit several weaknesses and the majority of these protocols are based only on a single hard problem. In this paper, we propose a new secured key exchange protocol which is based on two hard problems. We then extend this to a signcryption protocol and a deniable signcryption protocol. These protocols represent the first steps in a new direction, but they are designed based on two hard problems. The security proofs for the new protocols confirm their novelty and security.