Game-Theoretic Security of Commitment Protocols under a Realistic Cost Model

This paper considers game-theoretic security of bit commitment protocols under a realistic cost model. Higo et. al (IWSEC 2013) proved equivalence of game-theoretic security and cryptographic security of bit commitment protocols under an ideal cost model. Their model assumes that there is no cost for communication and computation. Under a realistic model that cost for communication and computation is non-negligible, this paper shows that conventional bit commitment protocols are not game-theoretically secure, and abort detection property is necessary for bit commitment protocols to achieve game-theoretic security.