A novel chaos-based approach for constructing lightweight S-Boxes.

Cryptography is the science of using specific secret writing techniques to convert an original message into a coded form for safe transmission over public networks. While conventional cryptographic techniques are efficient on resource-rich devices (e.g., PCs, servers, smartphones), they may perform poorly on the Internet of Things (IoT) devices with limited resources (e.g., Radio Frequency Identification (RFID) tags, sensors). Consequently, a specialized approach known as Light-Weight Cryptography (LWC) is necessary. The Substitution-Box (S-Box) is a crucial and distinct component in constructing cryptographic algorithms that introduces nonlinearity between inputs and outputs. This paper uses chaotic maps to present a novel approach for constructing 4 × 4 S-Boxes tailored for LWC with strong cryptographic properties. The method initially employs an enhanced sine map, followed by a combination of an enhanced logistic map and an enhanced tent map. This approach optimizes multiple parameters by a defined security threshold. The evaluation of the generated 4 × 4 S-Boxes confirms their optimal performance in the context of the Strict Avalanche Criterion (SAC), the Bit Independence Criterion (BIC), and enhanced resistance to Side Channel Attack (SCA), outperforming existing S-Boxes. Furthermore, successfully obscuring image features demonstrated their effectiveness in image encryption. We assessed the hardware efficiency of one of the generated S-Boxes by calculating its Gate Equivalent (GE) using the NanGate 45nm technology. The highly secure S-Boxes constructed in this study can serve as replacements for similar-sized S-Boxes in existing algorithms or be utilized to construct lightweight block cipher algorithms.