UIGen: a hybrid framework for underwater image encryption based on evolutionary chaotic system and multi-domain transformation.

Underwater images play a crucial role in advancing marine research, enhancing surveillance and ensuring secure communication. However, underwater image security is a significant concern due to the unique transmission and distortion vulnerabilities present in the aquatic environment. Factors such as light scattering, absorption, turbidity and limited bandwidth can degrade image quality, distort visual features and increase vulnerability to cyber threats. These environmental challenges make it difficult for existing encryption methods to simultaneously ensure high security and preserve image fidelity under submerged conditions. In response this study presents UIGen, a novel and secure encryption method specifically designed for underwater images that addresses the inherent security challenges of the aquatic environment while ensuring the confidentiality and integrity of the images. It employs Non-Subsampled Shearlet Transform (NSST) technique to extract multi-scale features from underwater images, enabling effective representation of both coarse and fine details. A dynamic key generation approach based on a hyper-chaotic parameter is used to increase key sensitivity and strengthen the overall encryption security. Finally, a Genetic Algorithm (GA) is applied to optimize the encryption parameters, enhancing the robustness of the system and ensuring its adaptability to varying underwater conditions. Experimental results demonstrate that UIGen maintains robust structural integrity and strong entropy while resisting underwater-specific attacks and enabling high-fidelity image encryption and storage.