%0 Journal Article %T Cryptanalyzing a discrete-time chaos synchronization secure communication system %A Gonzalo Alvarez %A Fausto Montoya %A Miguel Romera %A Gerardo Pastor %J Physics %D 2003 %I arXiv %R 10.1016/j.chaos.2003.12.013 %X This paper describes the security weakness of a recently proposed secure communication method based on discrete-time chaos synchronization. We show that the security is compromised even without precise knowledge of the chaotic system used. We also make many suggestions to improve its security in future versions. %U http://arxiv.org/abs/nlin/0311046v1