International Association
for Cryptologic Research

We initiate the study of unique group signature such that signatures of the same message by the same user will always have a large common component (i.e., unique identifier). We present a number of unique group signature schemes under a variety of security models that extend the standard security models of ordinary group signatures (without random oracles). Our work is a beneficial step towards mitigating the well-known group signature paradox, and it also has many other interesting applications and efficiency implications.