Group Signatures with Equality Test on Signers
Kyoya Anzai, Masayuki Fukumitsu, Hiroaki Anada, Shingo Hasegawa · 2022
We propose a new variant of group signature scheme which has the function of equality test on signers (GSET). When two signers who belong to different groups issue group signatures, our scheme enables a new entity “equality tester” to verify whether or not the signers of them are the same while maintaining anonymity. We introduce the syntax, security definitions and a generic construction of our GSET. In addition to the functions of an ordinary group signature scheme by Bellare, Shi and Zhang (at CT-RSA 2005), the equality-test function of GSET utilizes a “SemiOpen” algorithm with an equality key, which keeps the anonymity by working on hash values of identity data.