对一种基于logistic映射的分组加密机制的分析和改进

Cryptanalysis and improvement of a block cryptographic scheme based on logistic map

对一种改进的混沌分组密码机制分析后发现其本质上是流密码系统,并且密钥流与明文无关。通过选择明文攻击,在很小的计算代价下获得了密钥流。给出了选择明文攻击的算法,并通过实验进行了验证。为克服原加密算法的缺陷,采用密文反馈的形式使密钥流与明文相关。

Through analyzed of an improved chaotic block cryptographic scheme, it was found that this scheme behaves as a stream cipher indeed and generated keystream is independent with plaintext. By means of chosen plaintext attack, the keystream used can easily be recovered with little computing. The algorithm a chosen plaintext attack was proposed and validated by experiment. In order to avoid the flaw, a remedy which makes keystream dependent with plaintext though ciphertext feedback was suggested while keeping all the merits of the original cryptosystem.