中文摘要：

在实际应用中，前向安全性和公开验证性对密码系统来说是非常重要的。分析了不使用Hash和Redundancy函数的签密方案的前向安全性和公开验证性，分析表明该方案不具备前向安全性和公开验证性。分别就其前向安全性和公开验证性提出了相应的改进方案，并对方案进行了理论上的证明。改进方案克服了原方案中不具备前向安全性或公开验证性的缺陷；而且从效率上来分析，并没有明显增加计算量或传输量。

英文摘要：

In practical applications, the forward security and public verifiability are very important to cryptography. An authenticated signcryption without using Hash and Redundancy functions is analyzed in this paper, and the result indicates that the scheme does not possess the characters of forward security and public verifiability. Modified schemes are proposed respectively according to each character mentioned above, and theoretically proved. By adop- ting the modified schemes, the original scheme＇s defects of non - forward - security or non - public - verifiability are overcome, and the computational cost and communication overhead are not increased.