无Hash或冗余函数数字签密方案的分析与改进

摘要

对不使用 Hash 或冗余函数的数字签密方案进行分析，指出柏骏方案和于永方案均可被消息接收者伪造签名攻击，给出两种攻击方案，指出李方伟方案无前向安全和公开验证消息机密性。提出一个新的无 Hash 或冗余函数的数字签密方案，方案具有前向安全性和公开验证消息机密性，并进行了正确性和安全性分析。接收者无法进行伪造签名攻击，与已有方案比较，降低了算法复杂度。%We analysed the digital signcryption scheme not using Hash or redundant function,and pointed out that neither the scheme proposed by Bai Jun.nor the scheme by Yu Yong.can prevent the forgery signature attacks by the receiver of message.We also presented two attack schemes,and pointed out that the scheme proposed by Li Fangwei.hasn’t the forward security and the confidentiality in public verifiability.We proposed a new digital signcryption scheme without Hash or redundant function,and this scheme has forward security and confidentiality in public verifiability.We analysed its correctness and security as well.The message receiver cannot make the forgery signature attack,it decreases the complexity of the algorithm compared with existing scheme.