Cryptology ePrint Archive: Report 2009/592

From Passive to Covert Security at Low Cost

Ivan Damgård and Martin Geisler and Jesper Buus Nielsen

Abstract: Aumann and Lindell defined security against covert attacks, where the adversary is malicious, but is only caught cheating with a certain probability. The idea is that in many real-world cases, a large probability of being caught is sufficient to prevent the adversary from trying to cheat. In this paper, we show how to compile a passively secure protocol for honest majority into one that is secure against covert attacks, again for honest majority and catches cheating with probability 1/4. The cost of the modified protocol is essentially twice that of the original plus an overhead that only depends on the number of inputs.

Category / Keywords: cryptographic protocols / covert adversary

Publication Info: The paper has been accepted for TCC 2010; this is the full version.

Date: received 2 Dec 2009, last revised 4 Dec 2009

Contact author: mg at cs au dk

Available format(s): PDF | BibTeX Citation

Version: 20091204:093524 (All versions of this report)

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