Digital Images Security Technique Using Hénon and Piecewise Linear Chaotic Maps

The security of images has become a hot research area due to the widespread usage of the digital images all over the world. Literature review on chaotic image cryptography, on the other hand, indicates that many constructs have been employed for the realization of confusion operation while developing the image ciphers. To enhance the computational time, this study proposes a novel image cipher based on two chaotic maps and rectangle as a scrambler. As the given grayscale image is input, it is scrambled through dynamically generated rectangles. As a modus operandi, these rectangles are created in the given image with various dimensions and different location. The pixels lying on the boundary of the rectangle are rotated clockwise and anticlockwise with an arbitrary amount. These operations have been repeated a number of times to get the scrambling effects. The scrambled image has been further subjected to an XOR operation for embedding the diffusion effects in it. Two chaotic maps of Hénon and piecewise linear chaotic map have been used for the generation of random numbers. These numbers help in deciding the size, location, clockwise/anticlockwise movement of the pixels and the amount with which these pixels have to be rotated. The performance analysis and the machine simulation validate that the suggested cipher is sufficient enough to thwart the varied cryptanalytic attacks. In particular, we gained the computational speed of 0.5156 seconds and the information entropy of 7.9975. Besides, we posit that it has the ample prospects for its real world application.