A simple protocol for deniable authentication based on ElGamal cryptography

Abstract

Deniable authentication is different from traditional authentication in that the receiver cannot prove the source of a given message to a third party. This article presents a new deniable authentication protocol, based on ElGamal cryptography. The protocol meets the two properties of deniable authentication and can withstand person-in-middle (PIM) attacks. Compared with previous schemes, it is simpler and more efficient.

An improved deniable authentication protocol

“…In [9], the authors claim that their protocol could resist the person-in-the-middle attack. However, in this section, we shall show that the WLT protocol suffers from this kind of attack.…”

“…Recently, based on some problems (e.g., the factoring problem and the discrete logarithm problem), several protocols have been proposed [6][7][8]. In 2005, Wang et al [9] proposed an efficient deniable authentication protocol (WLT), which makes use of the inverse of the ElGamal cryptosystem; moreover, it requires reduced computational complexity and communication cost than the existing protocols [1-5, 7, 8].…”

Robust Deniable Authentication Protocol

“…Especially, in 2005, Wang et al [10] proposed an efficient deniable authentication protocol (WLT), which makes use of the inverse of the ElGamal cryptosystem [17]; moreover, it requires reduced computational complexity and communication cost than the existing protocols. In 2006, Shao et al [11], however, pointed out that the WLT protocol is insecure to a person-in-the-middle attack.…”

“…The deniable authentication protocol is a new technique of modern cryptography [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]. Compared with traditional authentication, it has two characteristics.…”

“…Their protocol adopted certificates to defeat the attack of a person-in-middle and signatures to identify the source of a given message. Thereafter, numerous deniable authentication protocols were proposed by many researchers in more recent years [5][6][7][8][9][10][11][12][13][14][15].…”