A novel image encryption scheme based on a linear hyperbolic chaotic system of partial differential equations

Compared with general chaotic systems, a linear hyperbolic chaotic system of partial differential equations with nonlinear boundary conditions has larger parameter space, stronger sensitivity to initial condition and control parameter, better random-like behavior and so on, but it has not been employed in cryptography so far. Then using its significant properties, we present a new cryptosystem with coupled map lattices and time-varying delay. The proposed image encryption algorithm with permutation–diffusion architecture can overcome some drawbacks in the existing methods, because the sum of pixel value of original image is used for determining the permutation parameters and the previous cipher image information is utilized in the next diffusion. Theoretical analysis and computer experiments confirm that the new algorithm is efficient, practicable, and reliable, with high potential to be adopted for network security and secure communications.

► Image encryption based on PDE is proposed for the first time.
► The plain-image information is considered to generate keystream in the permutation stage.
► CML and time-varying delay are utilized in the diffusion stage.
► The information of the former cipher image is associated to encrypt the current plain image.