一个预防欺诈的(t,n)门限数字签名方案

基于离散对数的安全机制，该文提出了一个预防欺诈的ElGamal型(t, n)门限数字签名方案。在密钥生成阶段，参与者的公、私钥以及群公钥由所有参与者共同协商而无需可信中心支持；在签名生成阶段，参与者之间不需要进行任何安全通信；能够抵御合法参与者间的相互欺诈和外部攻击者的攻击。方案的安全性是基于离散对数问题的难解性。分析发现，该方案具有良好的安全性和执行效率。

A (t, n) Threshold Digital Signature Scheme with Ability to Identify Cheaters

Based on the security mechanism of the discrete logarithm, an ElGamal-like (t, n) threshold digital signature scheme with ability to identify cheaters is proposed in this paper. In the key generation phase, each participant’s public and private keys, and the group public key are negotiated among all the participants with no trusted party required. In the signature generation phase, no secure communication is needed between any two participants. This scheme provides the capability of detecting cheating and identifying the cheater that may be from the internal legal participants or the external attackers. The security of this scheme is based on the difficulty of solving the discrete logarithm problem. Analyses show that this scheme is a computationally secure and efficient scheme.