New Image Encryption Algorithm based on Pixel Confusion-Diffusion using Hash Functions and Chaotic Map

Information privacy and security has become a necessity in the rapid growth of computer technology. A new algorithm for image encryption is proposed in this paper; using hash functions, chaotic map and two levels of diffusion process. The initialization key for chaos map is generated with the help of two hash functions. The initial seed for these hash functions is the sum of rows, columns and pixels across the diagonal of the plain image. Firstly, the image is scrambled using quantization unit. In the first level of diffusion process, the pixel values of the scrambled image are XOR with the normalized chaotic map. Odd pixel value is XOR with an even bit of chaotic map and even pixel is XOR with an odd bit of chaotic map. To achieve strong encryption, the image undergoes a second level of diffusion process where it is XOR with the map a finite number of times. After every round, the pixel array is circular shifted three times to achieve a strong encrypted image. The experimental and comparative analysis done with state of the art techniques on the proposed image encryption algorithm shows that it is strong enough to resist statistical and differential attacks present in the communication channel.