摘要： 利用密钥输出序列的相关性，对一个演化密码体制的安全性进行了系统的分析。通过分析可以得出：当已知连续128bit的密钥输出序列时，该密码体制的密钥空间规模将由2256下降到2128。当已知连续256bit的密钥输出序列时，该密码体制的密钥空间规模将由2256下降到284，并且在容许最多4个含错方程的情况下，密钥空间的规模将降低到272。因此，从选择明文攻击的角度来说，该密码体制的安全性是极其脆弱的。

关键词: 演化密码体制, 演化计算, 遗传算法, 密码分析

Abstract: This paper provides a systematic analysis for the security of an evolutionary cryptosystem by the correlation of the key output sequence. The analysis result is as follows: if continuous 128 bits of the key output sequence are known, the key space scale of the cryptosystem decreases from 2256 to 2128. If continuous 256 bits of the key output sequence are known, the key space scale of the cryptosystem decreases from 2256 to 284, moreover, the key space scale of the cryptosystem decreases to 272 under the condition that the number of error equations is no more than 4. The result shows the evolutionary cryptosystem is very insecure under chosen-plaintext attacks.

Key words: evolutionary cryptosystem, evolutionary computing, genetic algorithm, cryptanalysis

中图分类号: 

• TP309