【摘要】 Z.Shao提出了两种签名方案,并宣称它们的安全性是基于大数分解问题和离散对数问题的。其实,这两种签名方案在代换攻击下是不安全的。本文给出了伪造签名的公式,同时还提出了几种带有信息恢复功能的签名方案,它们的安全性是基于上述两个难题的,并且,它们在实施中的效率要比现有的方案好。更多还原

【Abstract】 In [2], the author proposed two signature schemes and suggested that the security of them is based on factoring and discrete logarithm problems. In fact, these schemes are vul-narable to substitution attacks. Formula to forgesignatures are presented. We also propose some signature schemes based those two hard problems with message recovery which are more efficient in implimentation.更多还原