Cryptanalysis of chaotic stream cipher by means of evolutional algorithms

Abstract

Stream ciphers are essential in digital communications working in real-time. A key-stream which is used fir the encryption purposes is usually created by pseudorandom number generators. These generators can be implemented as chaotic systems with quantization unit. As a result, a binary sequence represented the key-stream is obtained. When a cryptanalyst want to break this type of stream cipher, he must reveal an initial condition of the chaotic system which produces the key-strewn. This paper investigates possibilities of evolutional algorithms for the searching for that initial condition. Experiments show very promising results in breaking chaotic stream ciphers.