A color image encryption algorithm with a novel coupled chaotic system and 3D-DCT

Abstract

In order to improve the security of image transmission and reduce the complexity of encryption algorithm, an efficient color image encryption algorithm is developed based on 3D-DCT and coupled chaotic system. Firstly, the plain color image is decomposed into three grayscale plain images, which are transformed by DCT to obtain the corresponding frequency coefficient matrices. Then, the novel 2-D chaotic system is designed and used to generate the embedded matrices, which is implanted to the frequency coefficient matrices and forms the embedded frequency coefficient matrices. And then, the embedded matrices were scrambled and encrypted by Diagonal scrambling method and the encryption matrix generated by the 2-D chaotic system respectively, which resulted in the production of the ultimate color cipher image. In order to meet the requirement of the era of big data, the hash function SHA-256 is introduced to generate the key of encryption algorithm. This scheme is thoroughly validated on different sized plain-images with modern statistical analyses to prove the security and sensitivity. Eventually, compared with other schemes further demonstrates its competence and superiority in robustness and anti-interference.