Affiliations: [a] Institute of Computer Science, University of Tartu, Tartu, Estonia | [b] Department of Informatics and Telecommunications, National and Kapodistrian University of Athens, Athens, Greece
Correspondence:
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Corresponding author: Helger Lipmaa, Institute of Computer Science, University of Tartu, J. Liivi 2, 50409 Tartu, Estonia. E-mail: helger.lipmaa@gmail.com
Abstract: We propose a new non-interactive perfect zero-knowledge (NIZK) shuffle argument that, when compared with the only previously known efficient NIZK shuffle argument by Groth and Lu, has a small constant factor times smaller computation and communication, and is based on more standard computational assumptions. Differently from Groth and Lu who only prove the co-soundness of their argument under purely computational assumptions, we prove computational soundness under a necessary knowledge assumption. We also present a general transformation that results in a shuffle argument that has a quadratically smaller common reference string (CRS) and a small constant factor times longer argument than the original shuffle. This can be interpreted as a general technique of decreasing the offline cost of an arbitrary shuffle argument.
