An Efficient S‐Box Generation With Mutation Optimization for Secure Image Encryption
Aqeel Ejaz, Ghulam Murtaza, Takreem Haider, Naveed Ahmed Azam, Umar Hayat · Security and Privacy · 2025
ABSTRACT Efficient generation of substitution boxes (S‐boxes) with strong cryptographic properties is essential for securing modern digital systems, particularly in resource‐constrained environments such as the Internet of Things (IoT) and cloud computing. However, constructing dynamic S‐boxes often incurs significant computational overhead, which can affect encryption performance. We propose an efficient S‐box generation algorithm that combines elliptic curve point generation with a mutation‐based optimization. Our approach constructs cryptographically robust S‐boxes in three stages: (1) generating points on an elliptic curve over a finite field, (2) generating an initial S‐box from these points, and (3) applying a mutation operation to improve nonlinearity and other cryptographic properties. Experimental evaluations demonstrate that the proposed method generates a secure S‐box on an average of 0.0009 s and produces 10,000 randomized S‐boxes in 1.2169 s. Comparative analysis indicates that our generator operates at a speed of at least eight times faster than existing state‐of‐the‐art generators, without compromising security against standard cryptanalytic attacks. We further validate the practical utility of our generator in the context of image encryption. The results show that the method effectively secures the image data, even when the original image exhibits high inter‐pixel correlation, highlighting its applicability to real‐world cryptographic systems.