Anonymous Authentication with Spread Revelation

Abstract

This paper argues for the introduction of better privacy mechanisms and greater anonymity in electronic transactions. The introduction contains an overview of related work—namely group signatures and e-cash systems. Next, we present an original solution based on Σ-protocols, which leads to a scheme providing anonymous client authentication without any loss of client responsibility. The preserved client responsibility is assured by the spread revelation feature. This allows the identification of malicious users by the cooperation of two entities—namely, a service provider with a newly introduced Public Authority entity. Finally, we analyze the presented scheme from the point of view of security and efficiency.

Keywords:

• anonymity
• authentication
• group signatures
• privacy
• Σ-protocols

Acknowledgments

This work was sponsored under the National Program of Research II by the Ministry of Education, Youth and Sports of the Czech Republic in 2C08002 Project—KAAPS Research of Universal and Complex Authentication and Authorization for Permanent and Mobile Computer Networks.

The authors would like to thank Karel Burda for his comments, advice and support.