Chaotic-Lattice Feistel Cipher (CLFC): A Post-Quantum Secure and Lightweight Cryptographic Framework for Resource-Constrained IoT Edge Devices

The rapid growth of the Internet of Things (IoT) and edge computing has revolutionized real-time data processing through decentralized decision-making. However, ensuring the security of resource-constrained edge devices, particularly against emerging quantum threats, presents a significant challenge. Traditional encryption schemes such as RSA and AES, though robust, impose considerable computational and memory overhead, making them unsuitable for low-power IoT environments. Moreover, many existing solutions prioritize network-level security while neglecting device-level cryptographic constraints. This paper introduces the Chaotic-Lattice Feistel Cipher (CLFC), a lightweight and post-quantum secure cryptographic framework tailored for IoT edge devices. CLFC integrates an Extended Generalized Feistel Network (EGFN) for efficient data diffusion, a novel chaotic 5-bit S-box for enhanced non-linearity in key scheduling, and Ring-Learning with Errors (Ring-LWE) for quantum-resilient master key generation. Experimental results show that CLFC reduces execution time by up to 19% compared to Ascon and 45% compared to Elephant, while requiring zero heap memory allocation—making it well-suited for constrained environments. Security analysis confirms that CLFC achieves strong resistance against classical cryptanalytic techniques, including linear, differential, and meet-in-the-middle (MitM) attacks. These findings position CLFC as a computationally efficient, memory-optimized, and quantum-resistant encryption scheme for securing next-generation IoT and edge computing systems.