Paper 2017/587
Subversion-zero-knowledge SNARKs
Georg Fuchsbauer
Abstract
Subversion zero knowledge for non-interactive proof systems demands that zero knowledge (ZK) be maintained even when the common reference string (CRS) is chosen maliciously. SNARKs are proof systems with succinct proofs, which are at the core of the cryptocurrency Zcash, whose anonymity relies on ZK-SNARKs; they are also used for ZK contingent payments in Bitcoin. We show that under a plausible hardness assumption, the most efficient SNARK schemes proposed in the literature, including the one underlying Zcash and contingent payments, satisfy subversion ZK or can be made to at very little cost. In particular, we prove subversion ZK of the original SNARKs by Gennaro et al. and the almost optimal construction by Groth; for the Pinocchio scheme implemented in libsnark we show that it suffices to add 4 group elements to the CRS. We also argue informally that Zcash is anonymous even if its parameters were set up maliciously.
Note: This version incorporates the corrections of the BCTV14 scheme (ia.cr/2013/879, version 20190205) and some small fixes on p. 26.
Metadata
- Available format(s)
-
PDF
- Category
- Cryptographic protocols
- Publication info
- A major revision of an IACR publication in PKC 2018
- Keywords
- SNARKssubversion-resistancezero knowledgeZcash
- Contact author(s)
- fuchsbau @ di ens fr
- History
- 2020-05-16: last of 4 revisions
- 2017-06-20: received
- See all versions
- Short URL
- https://ia.cr/2017/587
- License
-
CC BY
BibTeX
@misc{cryptoeprint:2017/587,
author = {Georg Fuchsbauer},
title = {Subversion-zero-knowledge {SNARKs}},
howpublished = {Cryptology {ePrint} Archive, Paper 2017/587},
year = {2017},
url = {https://eprint.iacr.org/2017/587}
}
