Automaton-Based Lightweight Cryptography: Construction, Performance, and Differential Security Analysis

Abstract

This dissertation studies automaton-based lightweight cryptography for resource-constrained IoT devices. The primary contribution is the development of DH3-CBC, a hybrid cipher that extends the DH3 Latin-square stream cipher with a two-loop CBC-inspired chaining structure to achieve full bidirectional diffusion. The dissertation also presents the first complete differential cryptanalysis of both DH3-CBC and the DH4 block cipher, including exhaustive Difference Distribution Table computations and experimental verification of security bounds. Both ciphers are analysed under several adversarial models and shown to resist practical differential attacks at standard IoT payload lengths.