Self-shrinking chaotic stream ciphers

摘要

In the last two decades, a growing number of chaos-based cipher systems have been sug-gested for use in cryptographic applications. Most of these systems were subject to crypt-analytic attacks, and many of them were shown to suffer from a lack of security. In this paper, we export the self-shrinking technique used in classical cryptography into chaotic systems to develop chaotic keystream generators capable of generating keystreams featur-ing very good statistical properties, and possessing high level of security. This paper proposes a sample self-shrinking chaos-based keystream generator implemented using a 1-D chaotic tent map. Randomness properties and results of statistical testing of keystream bits generated by applying the self-shrinking technique on chaotic maps with suitable parameters are found encouraging. Furthermore, chaotic cipher systems based on such technique are demonstrated to have a better performance in terms of randomness proper-ties and security level than many existing cipher systems.