An efficient image encryption scheme based on Lorenz system and quantum-inspired walks.

Area of Science:

• Cryptography
• Information Security
• Quantum Computing

Background:

• Existing chaos-based image encryption methods struggle with low key sensitivity and static substitution, posing challenges for secure visual data transmission.
• Sophisticated cyber threats necessitate advanced cryptographic techniques for robust image information protection.

Purpose of the Study:

• To develop a highly secure multistage image encryption framework overcoming limitations of current methods.
• To enhance key sensitivity, diffusion, and confusion in image encryption algorithms.

Main Methods:

• Synergistic fusion of the Lorenz chaotic system, Secure Hash Algorithm 256 (SHA-256), and Discrete Time Quantum-inspired Walks (DTQWs).
• Utilizing bitwise modular operations for chaotic diffusion and dynamically constructing plaintext-dependent Substitution Boxes (S-Boxes) via DTQWs for confusion.
• Incorporating SHA-256 for a session-dependent quantum coin rotation parameter to ensure dynamic, plaintext-sensitive evolution.

Main Results:

• Achieved near-ideal entropy (7.9999), high NPCR and UACI rates, and correlation coefficients close to zero.
• Demonstrated high decryption reconstruction fidelity with PSNR = ∞ and NCC close to 1 for lossless recovery.
• Python-based evaluations confirmed outstanding security performance and robustness.

Conclusions:

• The proposed framework offers superior randomness, a balanced diffusion-confusion mechanism, and resilience against statistical and differential attacks.
• It presents a promising solution for secure image communication and high-assurance data protection in advanced multimedia systems.