Paper 2021/1674

Efficient and Post-Quantum Zero-Knowledge Proofs for Blockchain Confidential Transaction Protocols

Shang GAO, Tianyu ZHENG, Yu GUO, and Bin XIAO

Abstract

We propose new zero-knowledge proofs for efficient and post-quantum ring confidential transaction (RingCT) protocols based on lattice assumptions in Blockchain systems. First, we introduce an inner-product based linear equation satisfiability approach for balance proofs with a wide range (e.g. 64-bit precision). Unlike existing balance proofs that require additional proofs for some ''corrector values'' [CCS'19], our approach avoids the corrector values for better efficiency. Furthermore, we design a ring signature scheme to efficiently hide a user's identity in large anonymity sets. Different from existing approaches that adopt a one-out-of-many proof [CCS'19, Crypto'19], we show that a linear sum proof suffices in ring signatures which could avoid the costly binary proof part. We further use the idea of ''unbalanced'' relations to build a logarithmic-size ring signature scheme. Finally, we show how to adopt these techniques in RingCT protocols and implement a prototype to compare the performance with existing approaches. The results show our solutions can reduce about 25% proof size of Crypto'19, and up to 70% proof size, 30% proving time, and 20% verification time of CCS'19. We also believe our techniques are of independent interest for other privacy-preserving applications such as secure e-voting and are applicable in a generic setting.

Note: This is not the final version. The experiment part needs to be changed due to some major changes.

Metadata
Available format(s)
PDF
Category
Cryptographic protocols
Publication info
Preprint. MINOR revision.
Keywords
Lattice-based cryptographyzero-knowledge proofbalance proofring signatureRingCTblockchain
Contact author(s)
shanggao @ polyu edu hk
History
2022-05-17: last of 3 revisions
2021-12-21: received
See all versions
Short URL
https://ia.cr/2021/1674
License
Creative Commons Attribution
CC BY

BibTeX

@misc{cryptoeprint:2021/1674,
      author = {Shang GAO and Tianyu ZHENG and Yu GUO and Bin XIAO},
      title = {Efficient and Post-Quantum Zero-Knowledge Proofs for Blockchain Confidential Transaction Protocols},
      howpublished = {Cryptology {ePrint} Archive, Paper 2021/1674},
      year = {2021},
      url = {https://eprint.iacr.org/2021/1674}
}
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