Cryptology ePrint Archive: Report 2004/008

The Knowledge-of-Exponent Assumptions and 3-Round Zero-Knowledge Protocols

Mihir Bellare and Adriana Palacio

Abstract: Hada and Tanaka showed the existence of 3-round, negligible-error zero-knowledge arguments for NP based on a pair of non-standard assumptions, here called KEA1 and KEA2. In this paper we show that KEA2 is false. This renders vacuous the results of Hada and Tanaka. We recover these results, however, under a suitably modified new assumption called KEA3. What we believe is most interesting is that we show that it is possible to ``falsify'' assumptions like KEA2 that, due to their nature and quantifier-structure, do not lend themselves easily to ``efficient falsification'' (Naor).

Category / Keywords: zero-knowledge, foundations, assumptions, discrete log

Publication Info: A preliminary version appeared in Crypto 2004. This is the full version.

Date: received 10 Jan 2004, last revised 24 May 2004

Contact author: mihir at cs dot ucsd dot edu

Available format(s): Postscript (PS) | Compressed Postscript (PS.GZ) | PDF | BibTeX Citation

Version: 20040524:234225 (All versions of this report)

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