Cryptology ePrint Archive: Report 2017/309
Perfectly Secure Message Transmission Scheme against Rational Adversaries
Maiki Fujita and Takeshi Koshiba
Abstract: Secure Message Transmission (SMT) is a two-party cryptographic scheme
by which a sender securely and reliably sends messages to a receiver
using $n$ channels. Suppose that an adversary corrupts at most $t$
out of $n$ channels and makes eavesdropping or tampering over the
It is known that if $t < n/2$ then
the perfect SMT (PSMT) in the information-theoretic sense
is achievable and if $t\ge n/2$ then no PSMT scheme is possible to construct.
If we are allowed to use a public channel in addition to the normal channels,
we can achieve the almost reliable SMT (ARSMT),
which admits transmission failures of small probability,
against $t < n$ corruptions.
In the standard setting in cryptography,
the participants are classified into honest ones
and corrupted ones: every honest participant
follows the protocol but corrupted ones are controlled by the adversary and
As a real setting, the notion of rationality in the game theory
is often incorporated into cryptography.
In this paper, we first consider ``rational adversary'' who
behaves according to his own preference in SMT.
We show that it is possible to achieve PSMT even against any $t < n$
corruptions under some reasonable settings for rational adversaries.
Category / Keywords: cryptographic protocols / secure message transmission; game theory; rational adversary; secret sharing
Date: received 7 Apr 2017
Contact author: tkoshiba at waseda jp
Available format(s): PDF | BibTeX Citation
Version: 20170411:132858 (All versions of this report)
Short URL: ia.cr/2017/309
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