Title：An Abuse-Free Fair Contract Signing Protocol Based on the RSA Signature

Speaker：Dr. Guilin Wang 王贵林(University of Birmingham, UK)

Time：3:30pm, Tuesday,　April 20

Venue：815 Level 8 Building #5, Institute of Software, CAS

Abstract：(Presentation will be given in Chinese)

A fair contract signing protocol allows two potentially mistrusted parities to exchange their commitments (i.e. digital signatures) to an agreed contract  over the Internet in a fair way, so that either each of them obtains the other's signature, or neither party does. Based on the RSA signature scheme, a new  digital contract signing protocol is proposed in this paper. Like the existing RSA-based solutions for the same problem, our protocol is not only fair, but also optimistic, the third trusted party is involved only in the situations where one party is cheating or the communication channel is interrupted. Furthermore, the  proposed protocol satisfies a new property – abuse-freeness. That is, if the protocol is executed unsuccessfully, none of  the two parties can show the validity of intermediate results to others. Technical details are provided to analyze security and performance of the proposed protocol. In summary, we present the first abuse-free fair contract signing protocol based on the RSA signature, and show that it is both secure and efficient.

In particular, this talk will show how we can exploit appropriate tools (i.e., commitment scheme and zero knowledge protocol) to repair a simple but insecure contract signing protocol. This presentation is based on the following paper: Guilin Wang, An Abuse-Free Fair Contract Signing Protocol Based on the RSA Signature, IEEE Transactions on Information Forensics and Security, 5(1): 158-168, March 2010.

About the speaker：

Guilin Wang is currently a lecturer in the School of Computer Science, University of  Birmingham, UK. Before this, he was a research scientist in the Institute for Infocomm  Research (I2R), Singapore (06/2002-09/2007), and an assistant professor in the Institute of Software, Chinese Academy of Sciences (03/2001-05/2002). He received his PhD. degree in computer science from the Institute of Software, Chinese Academy of Sciences, China, in March 2001. Dr. Wang has served as a program co-chair for two international security conferences (ICICS'08 and ISA'09), a program committee member for more than 30 international information security related conferences or workshops, and a reviewer for more than 20 international journals. Up to
now, he has more than 50 technical publications in the areas of applied cryptography, information security, and electronic commerce. In particular, Dr. Wang is interested in the analysis and design of digital signatures and fair exchange protocols.