Certificate-based Fair Exchange Protocol of Schnorr Signatures in Chosen-key Model

Article type: Research Article

Authors: Shao, Zuhua^{a; *} | Gao, Yipeng^b

Affiliations: [a] No.210, Wulin Road, Hangzhou, 310006, P. R. China. zhshao_98@yahoo.com | [b] Ohio State University, Columbus, OH 43210, United States. gao.108@osu.edu

Note: [*] Address for correspondence: No.210, Wulin Road, Hangzhou, 310006, P. R. China.

Abstract: This paper proposes the first optimistic protocol to accomplish the fair exchange of standard Schnorr signatures in the chosen-key model, in which each participant is allowed to choose his Schnorr key pair freely without showing his knowledge of the private key. Besides solving the authentication problem of public keys, the protocol relaxes excessive trust on the adjudicator since the adjudicator needs to be trusted only by the signer. The protocol is secure against three types of inside adversaries under the DL assumption in the random oracle model. It suits much more the actual circumstances of the Internet.

Keywords: Fair exchange protocol, Schnorr signatures, Certificate-based, Chosen-key model

DOI: 10.3233/FI-2015-1265

Journal: Fundamenta Informaticae, vol. 141, no. 1, pp. 95-114, 2015