适用于Ad hoc网络的ElGamal型门限数字签名方案

ElGamal type threshold digital signature scheme for Ad hoc networks

现有ElGamal型门限数字签名方案在签名前签名各方需要协商生成一个随机数,该过程计算量与通信量比较大,不能满足Ad hoc网络的需求.将组合公钥的思想引入到ElGamal型门限数字签名的随机数生成中,为Ad hoc网络提出一种门限数字签名的改进方案.方案由密钥初始化和门限签名两部分组成.密钥初始化时,签名各方使用分布式密钥生成协议协商出系统公/私钥对和一个随机数矩阵,每个节点掌握部分私钥和部分随机数矩阵;门限签名时,每个签名方使用相同的算法在掌握的部分随机数矩阵中选择随机数进行部分签名;最后将部分签名合成整体签名.对提出的方案在随机预言(RO,Random Oracle)模型中进行了安全性证明.实用性分析表明:方案计算复杂度低,交互次数少,通信量小,有很好的执行效率与签名成功率.

ElGamal type threshold signature is an important part of threshold signature. There exists a problem in the EIGamal type threshold signature proposed before that all signer must generate corporately a random number before threshold signature is executed. The computation and communication overhead of the scheme is heavy and not suitable for Ad hoc networks. An improved E1Gamal type threshold signature scheme was proposed for Ad hoc networks. The composite public key （CPK） technology was used for generating ran- dom number. The scheme is composed of key initialization and threshold signature. All network nodes corporately generate a secret key and a random number matrix using distributed key generation protocol in the key initialization phase and every node hold secret key share and random number matrix share. When issuing part signature every signer select random number from its own random number matrix share using the same arithmetic. Then the part signature is used to reconstruct whole signature. The security of the scheme was proved in random oracle （RO） model. The practicability analysis shows that the computation complexity and the communication cost of the scheme are low, but the efficiency and success ratio are high.