Secure color image encryption using a fractional-order chaotic PRNG and DNA-level operations.

Area of Science:

• Cryptography
• Image Processing
• Applied Mathematics

Background:

• Conventional encryption methods are inadequate for large, complex color images due to data volume and redundancy.
• Existing chaos-based image encryption schemes often suffer from security vulnerabilities and insufficient randomness evaluation.
• There is a need for advanced encryption techniques that address the unique challenges of color image data.

Purpose of the Study:

• To propose a secure and effective color image encryption system.
• To integrate a fractional-order chaotic pseudo-random number generator (FCPRNG) with a DNA-level encryption framework.
• To address limitations of existing methods, including key space, plaintext dependency, and keystream randomness.

Main Methods:

• Developed a fractional-order chaotic pseudo-random number generator (FCPRNG) based on a fractional-order Lü system.
• Identified the admissible parameter-order joint space for sustained bounded chaos in the FCPRNG.
• Designed a plaintext-independent encryption framework and a DNA-level encryption architecture involving RGB permutation, pixel transformation, and DNA-domain operations.

Main Results:

• The FCPRNG produced statistically suitable pseudo-random number sequences.
• The proposed encryption scheme demonstrated strong ciphertext randomness and high sensitivity to key and plaintext.
• The system exhibited moderate robustness against common image distortions like noise and cropping.

Conclusions:

• The integrated FCPRNG and DNA-level encryption framework offers a structurally improved approach for color image security.
• The method provides an empirically effective solution for secure color image encryption, overcoming limitations of prior techniques.
• The plaintext-independent design and DNA-based operations enhance overall cryptosystem security and efficiency.