Self-synchronizing chaotic stream ciphers

Chaotic communication schemes aim to provide security over the conventional communication schemes. The sensitivity of chaotic systems/maps to their initial conditions and the parameters is used to introduce the security, where the latter is used as the secret key. The applicability of conventional chaotic systems/maps in communication channels with significant noise and multi-path is limited. Symbolic dynamics (SD) based methods have been shown to provide high quality synchronization (HQS). In this paper, a new digital chaotic communication scheme, which utilizes the SD based synchronization, is proposed. This is similar to a self-synchronizing stream cipher where synchronization information is provided periodically. For the proposed scheme, a theoretical expression for the upper bound of the bit error rate (BER) is derived. Numerical simulations are carried out to assess the BER performances of the system in AWGN and multi-path channels. Some security aspects of the proposed system are also studied. (C) 2008 Elsevier B.V. All rights reserved.