Cryptanalysis of a color image encryption using minimax differential evolution-based 7D hyper-chaotic map.

This paper proposes two attack methods to break the encryption algorithm using minimax differential evolution-based 7D hyper-chaotic map. In attack method 1, the secret keys generated by the 7D hyper-chaotic map can be directly revealed through two pairs of plain/cipher images. Once the secret keys are known, any cipher image can be decrypted easily. In attack method 2, we build three dictionary matrices of R, G and B channels firstly, and the corresponding plain image pixel value can be queried in the dictionary matrix one by one without using the secret keys or any system parameter. Experimental results demonstrate that the cryptosystem can be broken successfully by either of the proposed methods, thus avoiding the potential unexpected loss caused by the use of insecure encryption schemes. [ABSTRACT FROM AUTHOR]