首先构造了EDL签名方案中的阈下信道,然后设计了一个交互式阈下信道封闭协议,完全封闭了EDL签名中由参数的随机性所引入的阈下信道,并在RO(random oracle)模型中给出了安全性证明。在CDH(computational Diffie-hellman)问题是困难的假设下,新协议被证明是安全的。在新协议中,看守虽然参与了签名的生成,但却不能伪造签名,从而保证了签名者的签名权力。在计算量方面,签名者和看守分别执行2次和3次模指数运算。
Subliminal channels in EDL signature were constructed firstly,then an interactive subliminal-free protocol was designed.It is shown that the proposed protocol can completely close subliminal channels existing in the random parameters in EDL signature.The proposed protocol is proved to be secure in RO(random oracle) model assuming the CDH(computational Diffie-hellman) problem is hard.In the new protocol,the warden participates the generation of signature,but can not sign messages.Thus,the signature authority of the signer is guaranteed.To generate a signature,it only needs to perform 2 and 3 modular exponentiation for the signer and the warden respectively.