An Innovative Image/Text Encryption Technique using Fuzzy Substitution and Chaotic Key Expansion Module

Although many encryption techniques purport to provide adequate information protection, it is unclear how the struggle between these encryption techniques and constantly evolving hacking tools will play out. Cryptanalysis techniques are becoming more sophisticated and may soon challenge current encryption techniques. This paper proposes a new encryption technique that employs three effective and confusion-inducing methods. Specifically, the technique utilizes (1) an innovative key expansion technique that generates highly complex key sequences using chaotic means, (2) chaotic substitution that significantly transforms input symbols into different ones, and (3) a diffusion technique that induces a high avalanche effect in the output. The proposed technique was simulated on both plaintext and images and evaluated using standard NIST and ENT randomness testing as well as other effective testing techniques such as avalanche effect, pixel correlation, and entropy. The simulation results showed that the proposed encryption technique is secure and efficient for plaintext and image data.