Efficient Image Encryption Approach by Lorenz Chaotic Maps, SHA-256, and Discrete-Time Quantum Walks

This paper describes a novel image encryption scheme that combines Lorenz chaotic maps, the secure Hash Algorithm 256 (SHA-256), and Discrete-Time Quantum Walks (DTQWs). It exploits their sensitivity to their initial conditions, their innate capacity to produce complex randomness, and their adaptability for rapid computational procedures. The chaotic sequences resulting from the Lorenz maps undergoes are utilized in bitwise modular addition operations, for diffusion. DTQWs develop dynamic Substitution Boxes (S-Boxes), that increase confusion by modifying the adaptability of rows/columns. To achieve stronger security, SHA-256 is used to encrypt the plaintext in successive stages, producing hash-dependent quantum coin rotation angles and thereby injects plaintext sensitivity into S-Box construction. It guarantees high-level randomness, low correlation coefficients close to zero, and high immunity to statistical and differential attacks. Outcomes demonstrate better security and computation efficiency compared to available methods, qualifying it as an efficient and reliable solution for secure image transmission within present-day communication systems.