Double image compression-encryption algorithm based on fractional order hyper chaotic system and DNA approach

Abstract

In order to improve the efficiency and security of image compression-encryption algorithms, we propose a double image compression-encryption scheme based on fractional hyper-chaotic system and DNA approach. Firstly, two images are processed by discrete cosine transform. Secondly, the spectrums of the two images are sorted by Z-scan, so that the two images can be compressed and mixed into a new image. Finally, the resulting image is encrypted by using DNA coding. Different from traditional image encryption algorithms, the proposed algorithm provides a variety of DNA coding and operation modes. Chaotic sequences are used to control the coding and operation mode in order to improve the complexity of the encryption process. Fractional order and initial values of fractional order hyper-chaotic system are used as the key of the proposed algorithm, which greatly expands the complexity and the key space of the scheme. In the proposed scheme, by mixing two images and performing a compression-encryption operation on them simultaneously, the proposed algorithm can improve the complexity of encrypted images while providing good confusion. Experimental results and security analysis show that the proposed algorithm can effectively resist multiple attacks.