Non-interactive deniable authentication protocol based on factoring B Rongxing Lu * , Zhenfu Cao * Department of Computer Science, Shanghai Jiao Tong University, 1954 Huashang Road, Shanghai 200030, Peoples Republic of China Received 18 September 2004; accepted 20 September 2004 Available online 14 October 2004 Abstract Deniable authentication protocol is a new cryptographic authentication protocol that enables a specified receiver to identify the source of a given message, but not prove the identity of the sender to a third party. In recent years, many deniable authentication protocols have been proposed. However, most of these proposed schemes are interactive and less efficient. To our knowledge, only Shao has proposed an efficient non-interactive deniable authentication protocol based on generalized ElGamal signature scheme. Therefore, in this paper, we would like to propose another non-interactive deniable authentication protocol based on factoring. What’s more, we also prove it is secure in the random oracle model. D 2004 Elsevier B.V. All rights reserved. Keywords: Cryptography; Deniable authentication; Factoring 1. Introduction Deniable authentication protocol is a new crypto- graphic authentication protocol. Compared with the traditional authentication protocols, the deniable authentication protocol has two basic characteristics: (1) It enables a specified receiver to identify the source of a given message. (2) The specified receiver cannot prove to a third party the identity of the sender. Just as the above two characteristics, the deniable authentication protocol can be applied in some special situations. For instance, it can provide freedom from coercion in electronic voting systems and provide security of negotiation over the Internet [2]. In the past years, many researchers have done a lot of work in this field, and several deniable authenti- 0920-5489/$ - see front matter D 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.csi.2004.09.007 B This research is partially supported by the National Natural Science Foundation of China for Distinguished Young Scholars under Grant No. 60225007 and the National Resaerch Fund for the Doctoral Program of Higher Education of China under Grant No. 20020248024. * Corresponding authors. Tel.: +86 21 62932951; fax: +86 21 62932902. E-mail addresses: rxlu@cs.sjtu.edu.cn (R. Lu)8 zfcao@cs.sjtu.edu.cn (Z. Cao). Computer Standards & Interfaces 27 (2005) 401 – 405 www.elsevier.com/locate/csi