Design of a Cellular Automata-Based Permutation Network for Cryptographic Hash Functions

Cryptographic hash functions rely on efficient internal permutation mechanisms to achieve the diffusion and nonlinear transformations required for secure data integrity verification. This paper presents the design of a Cellular Automata-Based Permutation Network (CAPN) intended for integration into cryptographic hash functions. The proposed approach combines elementary and hybrid cellular automata with complementary nonlinear transformation stages to construct an internal state-transformation network capable of enhancing information diffusion and introducing dynamic state transformation throughout the hashing process. To validate the proposed design, the state-transformation network was integrated into a software implementation of a cryptographic hashing algorithm developed in C#. Multiple hash configurations with different digest lengths were implemented and experimentally evaluated. The obtained results indicate that the proposed state-transformation network achieves effective diffusion, producing avalanche effect values close to the theoretical optimum, while its software implementation exploits parallel bitwise operations for efficient state processing. These findings indicate that cellular automata may provide a unified design for internal permutation mechanisms in cryptographic hash functions and motivate further research on their cryptanalytic properties, performance optimization and integration into different hashing architectures.