A high-entropy image encryption scheme using optimized chaotic maps with Josephus permutation strategy.

Area of Science:

• Computer Science
• Cryptography
• Image Processing

Background:

• Digital data exchange necessitates robust image protection, especially in medicine, surveillance, and secure communications.
• Traditional encryption methods (DES, AES, RSA) are suboptimal for images due to pixel redundancy and correlation.
• Existing image encryption schemes often face challenges with speed and computational complexity.

Purpose of the Study:

• To develop a novel, resilient, and efficient image encryption algorithm overcoming limitations of traditional methods.
• To enhance image security through optimal diffusion and pixel confusion using chaotic maps.
• To improve key generation and reduce processing time while maintaining high encryption quality.

Main Methods:

• A novel image encryption algorithm combining chaotic maps and the variable-step Josephus problem.
• Kepler Chaotic Optimisation Algorithm (CKOA) for selecting optimal chaotic maps.
• MD5 and SHA-256 hash functions for secure key generation.
• Discrete Wavelet Transform (DWT) for image compression and reduced processing time.

Main Results:

• Achieved high average entropy of 7.999 for encrypted images.
• Demonstrated strong resistance to cryptographic attacks with a 99.6% pixel change rate and 33.31% unified average change intensity.
• The proposed algorithm offers superior security compared to existing schemes.

Conclusions:

• The novel image encryption algorithm provides enhanced security, speed, and reduced computational complexity.
• The integration of chaotic maps, Josephus problem, and DWT offers a robust solution for image protection.
• This method is highly suitable for sensitive image data in various critical sectors.