On the Security of a Group Signature Scheme with Forward Security

A group signature scheme allows a group member of a given group to sign messages on behalf of the group in an anonymous and unlinkable way. In case of a dispute, however, a designated group manager can reveal the signer of a valid group signature. Based on Song’s forward-secure group signature schemes, Zhang, Wu, and Wang proposed a new group signature scheme with forward security at ICICS 2003. Their scheme is very efficient in both communication and computation aspects. Unfortunately, their scheme is insecure. In this paper we present a security analysis to show that their scheme is linkable, untraceable, and forgeable.

• Type: Conference
• Year: 2003
• Where: ICISC
• Authors: Guilin Wang
• Keywords: Forward-secure Group Signature, Group Signature Scheme, ICISC 2003, ICISC 2007, Valid Group Signature