Li Shujun, Alvarez Gonzalo, Chen Guanrong, Mou Xuanqin
Department of Electronic Engineering, City University of Hong Kong, Kowloon, Hong Kong SAR, China.
Chaos. 2005 Mar;15(1):13703. doi: 10.1063/1.1856711.
This paper studies the security of a secure communication scheme based on two discrete-time intermittently chaotic systems synchronized via a common random driving signal. Some security defects of the scheme are revealed: 1) The key space can be remarkably reduced; 2) the decryption is insensitive to the mismatch of the secret key; 3) the key-generation process is insecure against known/chosen-plaintext attacks. The first two defects mean that the scheme is not secure enough against brute-force attacks, and the third one means that an attacker can easily break the cryptosystem by approximately estimating the secret key once he has a chance to access a fragment of the generated keystream. Yet it remains to be clarified if intermittent chaos could be used for designing secure chaotic cryptosystems.
本文研究了一种基于两个通过公共随机驱动信号同步的离散时间间歇混沌系统的安全通信方案的安全性。揭示了该方案的一些安全缺陷：1）密钥空间可显著缩小；2）解密对密钥不匹配不敏感；3）密钥生成过程在已知/选择明文攻击下不安全。前两个缺陷意味着该方案在抵御暴力攻击方面不够安全，第三个缺陷意味着攻击者一旦有机会访问生成的密钥流片段，就可以通过近似估计密钥轻松破解密码系统。然而，间歇混沌是否可用于设计安全的混沌密码系统仍有待阐明。
