Edinburgh Napier University

  Transmission of images over the Internet is exponentially increased in the last decade. However, Internet is considered as an insecure channel and hence may cause serious privacy issues. To overcome such privacy concerns, researchers are trying to secure image data from eavesdroppers through a method known as encryption. The final output of most traditional image encryption scheme is a random like noise. However, attackers pay special attention to such random/noise like images and hence these images are vulnerable to different type of attacks. In this paper, we propose a novel encryption scheme that can transform the plain-text image pixels into a visually meaningful encrypted image. In the proposed scheme, intertwining logistic map is used for introducing confusion and diffusion in plain-text images. Firstly, plain-text image pixels are permuted via random values obtained from chaotic map. In order to strengthen the proposed scheme, random values obtained from chaotic map are also XORed with the permuted image. In the final stage, Gray Substitution Box (S-Box) is applied to achieve the final cipher-text image. All experimental results such as key space analysis, noise attack and data loss attack are in the favor of the proposed scheme.