一个安全的动态门限签名体制

现有大多数门限签名体制存在一个共同的问题:门限值是固定的,这限制了它们的应用范围.基于离散对数计算问题的困难性提出了一个动态门限签名体制,有效地解决了上述问题.该体制允许在群体中共享多个组密钥,每个组密钥对应一个不同的门限值;可以根据文件的重要性而灵活地选取不同的门限值进行门限签名;每个签名者仅需保护一个签名密钥和一个秘密值;且不需要任何公共信息.分析表明,与已有体制相比,提出的体制能够抵御内部或外部攻击者的各种攻击,并可防止联合欺诈行为的发生,具有更好的安全性和实用性.

A Secure Dynamic Threshold Signature Scheme

In most available threshold signature schemes,only one group secret key is shared among a group of signers and the threshold value is fixed.However,in many occasions,the number of signers often depends entirely on the significance of the document.The solution usually is to construct a threshold signature scheme for different threshold value.It is obvious that there is a great deal of repeated computation and the efficiency is very low in this method.Motivated by this concern,based on the intractability of the discrete logarithm problem,a new dynamic threshold signature scheme that solves the above problem is proposed in the paper.In the proposed scheme,multiple group secret keys are shared among a group of signers,and each group secret key has its specific threshold value.Different group secret keys can be chosen flexibly to sign documents depending on their significance.Each signer needs to keep only one secret shadow and a secret value,and no public shadow is needed.Analyses show that,compared with the existing schemes,the proposed scheme can resist to various attacks from internal or external attackers,and protect the signature from allied cheating,which indicates that the proposed scheme is capable of providing more security and practicability.