Image Encryption and Decryption Using Chaotic - DNA Algorithm

In the era of digital multimedia, securing images during storage and transmission is paramount due to escalating cyber threats and the inherent vulnerabilities of traditional ciphers like AES to image-specific attacks such as differential and statistical analysis. This paper proposes an advanced hybrid Chaotic-DNA encryption scheme that integrates the unpredictability of chaotic logistic maps with the biochemical parallelism of DNA computing to provide robust confidentiality. The system generates pseudo-random sequences via a logistic map (parameter r=3.99 r=3.99, initial x0=0.5 x 0 =0.5) for pixel permutation, disrupting spatial correlations, followed by 8D DNA encoding (A, T, C, G bases) with XOR-based diffusion to enhance confusion. Extensive simulations on standard grayscale images (e.g., Lena 512×512) demonstrate superior performance: NPCR >99.61%, UACI ≈33.46%, pixel correlation near zero (-0.0012), and entropy 7.989 bits, outperforming AES, pure chaos, and DNA-only methods. The scheme exhibits high key sensitivity (10^{-15} change yields 99.8% difference) and low computational overhead (0.12s/image), making it ideal for real-time applications in telemedicine, military surveillance, and cloud storage. This dual-layer approach ensures lossless decryption and strong resistance to brute-force and known-plaintext attacks, addressing limitations of existing single-layer systems