Color Image Encryption Using S-Box Based on SHA-256 and Chaos Theory

Cryptography files can help prevent hackers from stealing encrypted information. On the other hand, current systems pose a high threat of security breaches or high computing demands. The suggested solution in this paper uses a low-cost encryption algorithm to improve security during communication while reducing computation costs and addressing the issues of secure color image transfer over an unsafe link. Two types of S-Boxes are employed as keys for encrypting a color image. The first one uses a hyperchaotic map (Logistic and Tent Maps) to the SHA-256 algorithm input, while the second relies on two types of chaotic maps (Logistic and Henon maps) to produce its contents. The encryption technique has divided into two phases. The first phase involves scrambling the pixels of the color image in its three channels using a modified diagonal scan algorithm. The second phase starts with splitting the original image into blocks (256 pixels in each block) before completing the encryption stage. An XORed operation is performed between each block and one of the resulting s-boxes. The encoded image is then sent through the Arnold transform to guarantee that the values are more scattered. Using chaos to generate two different forms of s-box dramatically increased propagation performance, allowing the encryption system to survive differential assaults. The correlation, histogram, entropy, and time analysis results illustrate the proposed system's dependability, effectiveness, and safety.