Paper 2005/178

Analyzing Unlinkability of Some Group Signatures

Zhou Sujing and Lin Dongdai

Abstract

Miyaji et.al proposed a fully functional(i.e., satisfying unforgeability, exculpability,anonymity, traceability, unlinkability, and revocability.) group signature over only known-order groups, that is based only on Discrete logarithm related assumptions, specifically, multiple DLP they proposed in the same paper [MU04]. In this paper, we point out their scheme and an improved scheme [ZZW05] do not have unlinkability.

Note: Correct some errors and add in some new information.