Design of a Fast Image Encryption Algorithm Based on a Novel 2D Chaotic Map and DNA Encoding

ABSTRACT Conventional DNA‐based encryption exhibits limited resistance against brute‐force attacks. To enhance image security, we propose an improved image encryption algorithm that integrates two‐dimensional chaotic mapping with optimized DNA encoding. First, a novel two‐dimensional chaotic mapping system is developed. The image is diagonally divided into upper and lower sections. The shorter columns are then systematically inserted into adjacent longer columns. A specialized linking mechanism first stretches the image into a linear sequence and then refolds it into a scrambled image that retains the original dimensions. Subsequently, DNA encoding is employed to induce pixel confusion and diffusion. The encryption key scrambles the original array, thereby enabling base substitution that generates an encoding lookup table. Following DNA‐based pixel encoding, lookup replacement and computational operations are executed prior to final decoding, which completes the encryption cycle. Experimental results confirm the algorithm's advantages, including an expansive key space, exceptional key sensitivity, efficient encryption performance, robust security, and practical implementation feasibility.