In this paper, an analysis study of two encryption algorithms applied to images is performed in order to assess their robustness in terms of security. The first is the classical cryptosystem known as Advanced Encryption Standard (AES) and the second is issued from the study of chaotic signals called the logistic map. The experimental results and their analysis show that AES encryptions is more secure, but on the other hand the logistic map exhibits good encryption speed.

In this article, we investigate image security for transmission in digital networks using a hybrid coding based on juxtaposed encryption and compression. We have proposed a new approach that integrates a dynamic Hill-Cipher encryption added to the step of quantizing of JPEG compression. A step by step demonstration is given in order to show the functioning of the crypto compression scheme constructed. This explanation justifies how to strategically integrate different operations of our crypto compression system. The effectiveness and robustness of our scheme is validated by measuring its security strength, its computational cost and the quality of reconstructed images (PSNR). The results showed that our new idea by both its generic fast encryption and its simple adaptation provides a reasonable complexity and a good compromise between security and compression rate, this crypto compression scheme is efficient and recommended for networks with low bandwidth especially for low-power devices.

In this paper, we propose a novel Dynamic Cipher Composition (DCC) based on multi-algorithm approach using the Library of Image Encryption Methods (LIEM). Unlike conventional static encryption schemes, the proposed DCC randomly selects and applies different encryption algorithms to spatially segmented regions of an image during each execution. To manage this process efficiently, the system employs two lightweight registers: one for configuration management and another for region-specific modality assignment, both indexed for streamlined storage and retrieval. Experimental evaluations conducted on standard test images demonstrate that the DCC achieves a near-optimal Shannon entropy, high values of Net Pixel Change Rate (NPCR) and Unified Average Changing Intensity (UACI), and negligible pixel correlation coefficients. These results confirm the scheme’s strong resistance to statistical, differential, and structural attacks, while preserving computational efficiency suitable for real-time applications such as telemedicine, cloud storage, and video surveillance systems.

This paper proposes an image encryption method using a spatio-temporal cryptographic diversification strategy. The implemented method, called Pseudo-Random Image Encryption System (PRIES), is based on three conceptual components: What (choice of methods), Where (spatial segmentation) and How (temporal assignment). The What component uses a cryptographic repository of image encryption methods (CRIEM) to pseudo-randomly provide, at each encryption cycle, a sequence of several different methods. The Where component employs a radial segmentation strategy inspired by the wavelet domain, segmenting the image into various angular segments to break spatial correlations. Finally, the How component implements a Markov model to pseudo-randomly assign the selected sequences, defined in the What component, to the angular segments defined in the Where component. On the operational level, experimental data demonstrate high robustness and cryptographic performance: an entropy close to 7.999, a pixel change rate (NPCR) greater than 99.6%, a uniqueness of pixel change index (UACI) approaching 33.46% and a very reduced processing time.