Chaos-Based Medical Image Encryption with Key Establishment Technique Using ChaCha20 and Diffie-Hellman Protocols
Sylia Amarouche, Saïd Talbi, Mehammed Daoui · Informatica · 2025
In healthcare, medical images are often transmitted over unsecured networks for consultation and diagnosis, exposing them to significant security risks. Therefore, it is crucial to implement effective encryption and key establishment schemes to preserve the integrity of this sensitive data. A critical issue is the repeated use or exposure of encryption keys, which increases the risk of compromise or interception. This paper proposes a novel key establishment technique for chaos-based encryption systems. This technique integrates the Diffie-Hellman protocol for asymmetric key agreement and the ChaCha20 stream cipher for secure stream encryption. These components are combined within a cryptosystem based on 2D Zaslavsky and Henon chaotic maps. The proposed technique preserves the integrity of medical image transmission without explicit key exchange and eliminates synchronization-induced errors introduced by conventional chaos-based systems. Experiments are conducted on 100 grayscale and RGB medical images of 256 × 256 and 610 × 610 resolutions. The evaluation is carried out using two 64 −