An image block encryption algorithm based on hyperchaotic system and DNA encoding

This paper presents an innovative image block encryption algorithm adopting fractional Fourier transform (FRFT), hyperchaotic system, improved logistic map and Deoxyribonucleic Acid (DNA) encoding. Initially, the plaintext image is performed FRFT twice, and the processed image is decomposed into three components according to the RGB channels. Then, three components and the matrix created by logistic map are divided into several sub-blocks. The sub-blocks are performed DNA encoding. Furthermore, perform DNA operation between the three components sub-blocks and the corresponding sub-blocks of the logistic matrix, and then decode and merge the sub-blocks into one image. Finally, chaotic sequences are used to scramble the merged images to gain the ciphertext image. The DNA encoding, decoding and operation rules of each sub-block are randomly determined by the chaotic sequences, which can effectively improve the complexity of DNA encoding, decoding and calculation rules. The algorithm possesses huge key space, high key sensitivity, extreme complexity and security demonstrated from simulation results and security performance analysis.