This project proposes a novel image encryption technique that combines the Normalized Exponential Piecewise Chaotic System (NEPCS) and DNA encoding to secure digital images. Traditional encryption algorithms such as AES and DES are inefficient for image encryption due to high pixel correlation and redundancy. The NEPCS system, characterized by its large chaotic range and high sensitivity to initial conditions, is employed to generate pseudo-random numbers for the encryption process. The image pixels are first transformed into DNA bases, followed by permutation and substitution using a combination of chaotic sequences and DNA complementary rules. A Cipher Block Chaining (CBC) mode of substitution, alternating XOR and addition operations, enhances the encryption process. The system’s effectiveness is evaluated using various statistical tests, including NPCR, UACI, and entropy, demonstrating its robustness against differential and statistical attacks. Additionally, key sensitivity analysis shows that minor changes in the encryption key result in significant differences in the output, ensuring strong security. The results confirm that the proposed NEPCS-DNA encryption scheme offers a high level of randomness, strong security, and resilience to cryptanalysis, making it a promising solution for secure image encryption in modern applications.

Keywords:
Image encryption, Normalized Exponential Piecewise Chaotic System (NEPCS), DNA encoding, Cipher Block Chaining (CBC), pseudo-random numbers, NPCR, UACI, entropy, cryptographic security, key sensitivity, differential attacks, statistical analysis.