A hyper-chaos-based image encryption scheme with double parity alternate scrambling

Due to the complex dynamic characteristics, randomness, larger key space and better sensitivity of hyper-chaotic system, it is very suitable for the application in image encryption. This paper mainly proposes a double parity alternate-based image encryption scheme with a four-dimensional hyper-chaotic system. The key stream, produced by the hyper-chaotic system, is closely relevant to the plain-text image. First of all, parity alternate scrambling is used to change the image pixel position, and then bit-plane parity alternate scrambling is used, which can not only change the position but also change the pixel value. Finally, the key stream generated by the hyper-chaotic system is used to diffuse the image to make the encryption system more secure. Additionally, the use of the double parity alternate scrambling and diffusion can make the pixel value distribution of the image be more uniform, and the given scheme is not only simple and easy to implement but also can resist some attacks effectively, such as differential attacks, statistical attacks, and etc. Theoretical analysis and numerical simulation show that the given scheme has good safety performance and good reliability for image encryption.