A chaotic image encryption algorithm based on coupled piecewise sine map and sensitive diffusion structure

This paper proposes a new chaotic system based on sine map, i.e., the coupled piecewise sine map (CPSM), which utilizes piecewise mechanism to obtain more uniform probability density distribution of state values, and enhances the complexity of chaotic system by coupling parameters between sub-systems. Then, from the view of resisting the chosen ciphertext attack, a ciphertext sensitive diffusion structure is presented. Based on the CPSM and the ciphertext sensitive diffusion structure, this paper proposes a new image encryption algorithm. Since the CPSM can generate chaotic sequences with good cryptographic properties and the diffusion structure has good diffusion performance in both the encryption process and the decryption process, the proposed encryption algorithm is extremely sensitive to the ciphertext tampering. Thus, it can effectively resist the chosen ciphertext attacks. Experimental results and security analysis also confirmed that the proposed algorithm has good security and can ensure the secure transmission of image in the Internet.