Cryptology ePrint Archive: Report 2010/462
Unconditionally Secure Rational Secret Sharing in Standard Communication Networks
Zhifang Zhang
Abstract: Rational secret sharing protocols in both the two-party and
multi-party settings are proposed. These protocols are built in
standard communication networks and with unconditional security.
Namely, the protocols run over standard point-to-point networks
without requiring physical assumptions or simultaneous channels, and
even a computationally unbounded player cannot gain more than
$\epsilon$ by deviating from the protocol. More precisely, for the
$2$-out-of-$2$ protocol the $\epsilon$ is a negligible function in
the size of the secret, which is caused by the information-theoretic
MACs used for authentication. The $t$-out-of-$n$ protocol is
$(t-1)$-resilient and the $\epsilon$ is exponentially small in the
number of participants. Although secret recovery cannot be
guaranteed in this setting, a participant can at least reduce the
Shannon entropy of the secret to less than $1$ after the protocol.
When the secret-domain is large, every rational player has great
incentive to participate in the protocol.
Category / Keywords: cryptographic protocols / rational secret sharing, $\epsilon$-Nash equilibrium, unconditional security
Date: received 30 Aug 2010, last revised 1 Nov 2010
Contact author: zfz at amss ac cn
Available format(s): PDF | BibTeX Citation
Version: 20101102:022421 (All versions of this report)
Short URL: ia.cr/2010/462
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