On Cryptanalysis Techniques in Chaos-based Cryptography

Since the 1990s, many chaos-based ciphers have been proposed and claimed to be secure by their designers. The designers of these ciphers usually use a set of statistical tests to manifest their security claims.It has been indicated that the commonly used statistical tests are insufficient to evaluate the security of these ciphers. Due to their inadequate cryptanalysis in the design stage, many of these ciphers reportedly have shown weaknesses in relatively simple attack scenarios and were broken in subsequent publications. This paper will investigate an evaluation methodology that appeared recently in chaos-based cryptography literature. The inadequacy of this methodology is demonstrated by presenting attacks on ciphers that pass this test. The attacks presented are of the same kind as those to which the suggested test is supposed to manifest a cipher's resistance. Hence, we concluded that the suggested test is unsuitable for showing a cipher's resistance to these attacks.