A symmetric key cryptosystem and hardware encryption module using non-linear reversible cellular automata

Abstract

This paper presents an encryption and decryption method using Cipher Block Chaining (CBC) combined with Large Cycle Reversible Non-Uniform Cellular Automata. The proposed approach utilizes an 8-bit rule vector that ensures both substantial cycle length and randomness, which are critical for effective cryptographic operations. The 8-bit cellular automaton (CA) is scaled to any length cellular automaton by repeating specific rules, minimizing the need for additional gates and maintaining cost efficiency. This CA serves as an encryption key that transforms plain text into an encrypted message without discernible patterns. We propose two block-cipher designs with block sizes of 64 and 128 bits. The encrypted output undergoes rigorous randomness testing using the Dieharder, NIST, and TestU01 test suites. An analysis of known and chosen plaintext attacks shows that these are not feasible. Additionally, a visual test is conducted to verify the randomness of the ciphertexts used. Finally, we propose a prototype hardware model for encryption using a 64-bit key that is robust and scalable. © The Author(s), under exclusive licence to Springer Nature B.V. 2025.