Design Trends and Comparative Analysis of Lightweight Block Ciphers for IoTs

This paper provides a comprehensive survey of 58 lightweight block ciphers (LWBCs) introduced between 2018 and 2025, designed specifically for securing resource-constrained environments such as the Internet of Things (IoTs). The ciphers are systematically categorized into five structural classes: substitution-permutation network (SPN), Feistel network (FN), generalized Feistel network (GFN), addition-rotation-XOR (ARX), and hybrid architectures. For each cipher, key characteristics—block size, key length, structural design, number of rounds, implementation cost in gate equivalents (GEs), and known limitations—are analyzed in detail. The study offers an in-depth comparative assessment of performance, security, and implementation efficiency, providing a clear understanding of design trade-offs and cryptographic innovations. By consolidating and evaluating recent advancements in lightweight cryptography, this survey fills a crucial gap in the literature. It equips researchers, engineers, and system designers with the insights needed to make informed decisions when selecting or developing efficient cryptographic solutions tailored for modern IoTs systems. Its comprehensive scope and practical relevance make it an essential reference for advancing secure, lightweight cryptographic implementations in an increasingly connected world.