Title: A novel secure key generation and SPN-based transformation algorithm for greyscale image encryption

Authors: Pramil Kesarwani; Ketan Puyad; Bharathi Chidirala; Bibhudendra Acharya

Addresses: Department of Electronics and Communication Engineering, National Institute of Technology, Raipur, Chattisgarh – 492010, India ' Department of Electronics and Communication Engineering, National Institute of Technology, Raipur, Chattisgarh – 492010, India ' Department of Electronics and Communication Engineering, National Institute of Technology, Raipur, Chattisgarh – 492010, India ' Department of Electronics and Communication Engineering, National Institute of Technology, Raipur, Chattisgarh – 492010, India

Abstract: In today's digital age, securing sensitive visual data is crucial, particularly in fields like medical imaging and secure communication. This paper presents a novel greyscale image encryption algorithm that combines a secure message-based key generation approach with a substitution-permutation network (SPN) for enhanced security. The algorithm uses a user-specified parameter 'N' an input image, and a secret message to derive cryptographic parameters via a SHA-256 string for a Henon map. The map generates two arrays, x and y matching the image dimensions, which are used to create an XOR-based mask. Before applying the mask, the image undergoes P-rounds of SPN transformations, involving substitution and permutation operations. These operations employ a logistic map for randomness, ensuring robust encryption. Decryption reverses these steps. The paper highlights the algorithm's computational efficiency and strong security features, making it suitable for diverse applications.

Keywords: secure key generation; Henon map; logistic map; SHA-256; substitution-permutation network; SPN.

DOI: 10.1504/IJICS.2025.147755

International Journal of Information and Computer Security, 2025 Vol.27 No.3, pp.307 - 332

Received: 02 Apr 2024
Accepted: 05 Nov 2024
Published online: 30 Jul 2025 *

Full-text access for editors Full-text access for subscribers Purchase this article Comment on this article