Witness Authenticating NIZKs and Applications

Hanwen Feng; Qiang Tang

Paper 2023/1276

Witness Authenticating NIZKs and Applications

Hanwen Feng

, The University of Sydney

Qiang Tang, The University of Sydney

Abstract

We initiate the study of witness authenticating NIZK proof systems (waNIZKs), in which one can use a witness $w$ of a statement $x$ to identify whether a valid proof for $x$ is indeed generated using $w$ . Such a new identification functionality enables more diverse applications, and it also puts new requirements on soundness that: (1) no adversary can generate a valid proof that will not be identified by any witness; (2) or forge a proof using some valid witness to frame others. To work around the obvious obstacle towards conventional zero-knowledgeness, we define entropic zero-knowledgeness that requires the proof to leak no partial information, if the witness has sufficient computational entropy. We give a formal treatment of this new primitive. The modeling turns out to be quite involved and multiple subtle points arise and particular cares are required. We present general constructions from standard assumptions. We also demonstrate three applications in non-malleable (perfectly one-way) hash, group signatures with verifier-local revocations and plaintext-checkable public-key encryption. Our waNIZK provides a new tool to advance the state of the art in all these applications.

Metadata

Available format(s): PDF
Category: Cryptographic protocols
Publication info: A major revision of an IACR publication in CRYPTO 2021
DOI: 10.1007/978-3-030-84259-8_1
Contact author(s): hanwen feng @ sydney edu au
qiang tang @ sydney edu au
History: 2023-08-28: approved; 2023-08-24: received; See all versions
Short URL: https://ia.cr/2023/1276
License: CC BY

BibTeX

@misc{cryptoeprint:2023/1276,
      author = {Hanwen Feng and Qiang Tang},
      title = {Witness Authenticating {NIZKs} and Applications},
      howpublished = {Cryptology {ePrint} Archive, Paper 2023/1276},
      year = {2023},
      doi = {10.1007/978-3-030-84259-8_1},
      url = {https://eprint.iacr.org/2023/1276}
}