Witness Authenticating NIZKs and Applications

Hanwen Feng, Qiang Tang

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Scopus citations


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 her 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.

Original languageEnglish (US)
Title of host publicationAdvances in Cryptology – CRYPTO 2021 - 41st Annual International Cryptology Conference, CRYPTO 2021, Proceedings
EditorsTal Malkin, Chris Peikert
PublisherSpringer Science and Business Media Deutschland GmbH
Number of pages31
ISBN (Print)9783030842581
StatePublished - 2021
Externally publishedYes
Event41st Annual International Cryptology Conference, CRYPTO 2021 - Virtual, Online
Duration: Aug 16 2021Aug 20 2021

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Volume12828 LNCS
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349


Conference41st Annual International Cryptology Conference, CRYPTO 2021
CityVirtual, Online

All Science Journal Classification (ASJC) codes

  • Theoretical Computer Science
  • General Computer Science


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