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.
@article{arxiv.nlin/0407052,
title = {Breaking a chaos-noise-based secure communication scheme},
author = {Shujun Li and Gonzalo Álvarez and Guanrong Chen and Xuanqin Mou},
journal= {arXiv preprint arXiv:nlin/0407052},
year = {2016}
}