基于椭圆曲线的三方比特承诺

Three-Party Bit Commitment Based on Elliptic Curve

比特承诺是安全多方计算中最重要的基础协议之一,对构建更复杂的多方协议起着重要作用。该文提出了三方比特承诺模型,在该模型中,由两个证明者共同向一个验证者作出承诺。给出了基于椭圆曲线的三方比特承诺方案,经证明,尽管该方案完全基于经典计算环境,但是并不需要对协议参与方的计算能力作任何限制性假设,具有无条件安全性且对信道窃听免疫。该方案同时可以推广到比特串承诺协议。

Bit commitment is a fundamental primitive in secure multi-party computation. It plays an important role in constructions of more complicated multi-party protocols. A new model of bit commitment named three-party bit commitment is proposed in this paper, in which two provers jointly commit a bit to a verifier. The protocol of three-party bit commitment based on elliptic curve cryptography is also given. The scheme is in purely classical means, without restricted assumptions of the computing power imposed on any participant. Moreover, the scheme is proven to be of unconditional security and be immune to channel eavesdropping. The protocol can also be modified easily to realize bit string commitment scheme.