Robust Image Encryption With Scanning Technology, the El-Gamal Algorithm and Chaos Theory

Digital images are the most frequently used signals to convey information in the internet era. The security of these images is the primary concern in rapidly changing networked environments. In this research, we present a novel approach to secure images by integrating a scanning technique, the El-Gamal public key cryptosystem and chaotic systems. In brief, zigzag and spiral scanning are used first to construct a permuted image. Then, the El-Gamal encryption algorithm is exploited to encrypt the permuted image. Finally, Lorenz and Rössler chaotic sequences are utilized to scramble the pixel locations in the confusion and diffusion stages. This last step that mixes two stages can fortify the entire security performance and enlarge the key size. Exhaustive analysis has been carried out on the SIPI (signal and image processing institute) dataset to assess the efficiency and security of the proposed method. Numerical and visual results indicate the capability of the proposed image cryptosystem to protect images against several known attacks. In addition, the comparative analysis results indicate that the proposed approach outperforms the compared approaches in terms of the visual quality and security criteria.