An Effective, Permutation-only, Bit-Level Image Encryption System Using Chaotic Maps

The widespread and growing utilization of digital images has elevated the significance of image encryption as a crucial concern, garnering significant attention from researchers. Regrettably, the current state of image encryption schemes lacks comprehensive development and research. This article presents a new image encryption system that uses only permutations and works at the bit level. The system incorporates chaotic maps to enhance its effectiveness. The method begins by executing the bit-plane generation process, which is then followed by the bit-plane concatenation operation. The bit-planes are individually subjected to bit-shuffling using distinct Logistic chaotic maps (LM) with varying key values. The shuffled outputs are vertically concatenated and then horizontally concatenated to execute the final stage of the bit-level shuffling operation. The output obtained from concatenation is subjected to a two-step shuffling process. First, a row-shuffling operation is performed, followed by a column-shuffling operation. Both shuffling operations are carried out using a separate LM system. The shuffled output is subjected to bit-plane separation and subsequently combined to produce the cipher image. The hash-based key values of LM systems enhance the method’s resistance towards the selected-plaintext and selected-ciphertext attacks. Based on the computer simulations and security analysis conducted, it has been determined that the proposed method has been demonstrated to be effective in encrypting images securely and efficiently.