Selective Image Encryption Using DCT and DES Algorithms

Abstract

Ensuring image security in digital communication is paramount, particularly in resource-constrained environments. Conventional encryption methods often struggle with balancing computational efficiency and security robustness for large multimedia files. This paper introduces a partial encryption framework that utilizes the Data Encryption Standard (DES) to selectively encrypt critical image regions while leaving non-sensitive areas intact, employing a new method based on specific frequencies of DCT coefficients. This approach significantly reduces processing overhead while maintaining a strong security layer over essential data. The suggested method uses DCT for image coding and then uses the accreditation approach that implements partial image encoding based on JPEG. This procedure is based on a technique that aims to keep the value of the public bit and to keep agreeing with the JPEG format; this includes multiple coding, enforceability, self-sufficiency, spatial selectivity, and coordination compliance, and how the application needs are met in real-time. The dataset of 10 images has been used to evaluate the suggested method. The results indicate that PSNR=31.05, coefficient correlation=0.96, entropy value is 7.71, and SSIM=0.97. These results, besides the histogram analysis, indicate a high level of randomness in encrypted images, good encryption, and low distortion in the decrypted images, uniform pixel intensity distribution across all encrypted images, ensuring resistance to statistical attacks, and demonstrating a strong disruption of pixel patterns post-encryption.