Chaos has been one of the most effective cryptographic sources since it was first used in image-encryption algorithms. This paper closely examines the development process of chaos-based image-encryption algorithms from various angles, including symmetric and asymmetric algorithms, block ciphers and stream ciphers, and integration with other technologies. The unique attributes of chaos, such as sensitivity to initial conditions, topological transitivity, and pseudo-randomness, are conducive to cross-referencing with other disciplines and improving image-encryption methods. Additionally, this paper covers practical application scenarios and current challenges of chaotic image encryption, thereby encouraging researchers to continue developing and complementing existing situations, and may also serve as a basis of future development prospects for chaos-based image encryption.

The performance of most chaotic systems is dependent on the selection of parameters, and an incorrect selection can lead to a significant reduction in the complexity and safety of chaotic systems or to chaotic degeneracy. In this paper, we investigate an Exponential Cyclic Coupling Chaotic Model (ECCCM) that maintains excellent and stable chaotic dynamics across a wide range of parameters. We use the Exponential Coupled Logistic Model (ECLM) as an example to design a new fast image encryption algorithm that treats the image as a three-dimensional matrix and simultaneously changes the positions and values of its pixels. Our proposed encryption algorithm has been verified through various experiments to be highly secure and competitive with other state-of-the-art algorithms.

With the continuous development of information technology, the security of images in the process of transmission, storage and use has also become the focus of network security. However, most of the existing image encryption algorithms only focus on the security of images in the transmission and storage process, while ignoring their security in use. For some special organisations, images are very sensitive information and their security during usage is also very important. Similar to the advanced encryption information stored in the public security system, the depth of information that can be viewed by ordinary privileges and advanced privileges is different. But there is no such hierarchical authorisation algorithm in image security. In order to solve this problem, this study proposes a hierarchical authorisation encryption and decryption algorithm, which achieves hierarchical decryption while ensuring the security of encrypted images. In this method, the image is decomposed by bit plane, and the bit plane is grouped, and each group adopts different key. According to the level of legitimate users, the corresponding key is assigned to them, and the clarity of the decrypted image requested by different levels of users is different, that is, the information depth is different. This method extends the scope of application of the encryption algorithm and is more practical than the existing encryption algorithm.