Cooperative group signature scheme with controllable linkability
- LIU Xin, XU Qiu-liang, ZHANG Bo
JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2016, 51(9):
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The existing group signature schemes with controllable linkability(abbreviated as GS-OL)suffer from the following two deficiencies, i.e., group members’ private keys are likely to leak and the Open Authority may harm users’ privacy. Moreover, there is still room for improvement in the computational efficiency of users. To correct this situation, an extension of the existing GS-OL security model was made, and an improved scheme with higher efficiency was provided. By using the Boneh-Boyen signature scheme without pairings, the users were liberated from performing expensive pairing computations. Borrowing the ideas of cooperative group signatures, the problem of private key leakage of group members was also solved. Moreover, in order to decentralize the Open Authoritys power, the technique of distributed key generation, committed zero-knowledge proof of knowledge, and distributed proof of knowledge of preimages of group homomorphism were incorporated in the new scheme. In addition, a practical anonymous subscription system based on the new GS-OL scheme was proposed. Compared with previous systems, the new system meets several practical properties such as allowing customers’ tokens to expire and supporting privacy-preserving data mining, and it has obvious advantage in users’ operational efficiency.