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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 advancement in digital communication poses a risk to the confidentiality of every individual. To protect information, chaos-based encryption is being exploited in recent research. The complexity of the algorithm is yielded by introducing a hyperchaotic map. This paper proposes a novel Two-Dimensional Henon Ikeda Map (2D-HIM) by combining the Henon map and the Ikeda map. The pseudo-random sequence is generated by the novel 2D-HIM applied to the DNA-based image encryption algorithm. This algorithm ensures the scrambling of pixels into an encrypted form that is unrecognisable. The cryptosystem has been analysed on various colour images, obtaining nearly an NPCR of 99.75%, a UACI of 33.84%, and an entropy of 7.99. Thus, the proposed algorithm ensures resistance against various statistical attacks and differential attacks, implying a robust solution to confidentiality in open communication and suitability for use in cryptographic applications.

In this paper, we analyze the security of a chaos-based image encryption algorithm. We find that the algorithm is vulnerable to differential cryptanalysis. The differential cryptanalysis demonstrates that the security of the original scheme depends only on the permutation key instead of on all of the keys, which makes the key space of the cryptosystem greatly reduced. Specifically, ( H × W + 1 ) chosen plain-images can reveal the equivalent permutation key for one-round encryption, where H × W is the size of the binary image. The two-way differential comparison method is proposed to break two-round cryptosystem. Basing on differential cryptanalysis, we propose a codebook attack under chosen-ciphertext conditions, design the codebook with ( H × W ) differential binary images, and totally break multi-round cryptosystem using XOR operation of O ( H × W ) images. The simulation results indicate that the designed codebook attack is effective. Furthermore, we summarize some characteristics of a class of permutation–diffusion systems that also are vulnerable to the differential attack and the codebook attack.

Securing digital images has become increasingly challenging due to the vast volume of images produced and transmitted across various platforms, coupled with the rising incidence of cybersecurity threats. Although attention has shifted toward utilizing hyperchaotic systems for image encryption, many cryptosystems that incorporate high-dimensional chaos along with other computationally intensive techniques face drawbacks, including speed limitations. Therefore, there is a pressing need for encryption schemes that are simple, fast, and sufficiently robust to meet the requirements of lightweight systems. This paper proposes a simple and efficient image encryption algorithm based on chaotic diffusion and random permutation. In this scheme, two low-dimensional chaotic systems are used to generate encryption keys, with one system being influenced by a SHA-256 hash value. The encryption process involves two rounds of chaotic diffusion interleaved with a random permutation to secure the images. The two distinct chaotic keystreams are applied at different stages of the encryption process to enhance randomness. Hashing is incorporated into keystream generation to ensure that the encryption key has a partial dependence on the image being encrypted. Pixel scrambling is performed mid-way by the permutation function to enhance randomness in the process. Experimental analyses, including key, differential, and statistical analyses, demonstrate that the proposed algorithm is fast, robust, and resistant to various types of security attacks on digital images.

As the demand for secure visual data transmission grows, specifically concerning the areas of medical imaging, surveillance, and secure communications, image encryption has emerged as a popular research area. Traditional ciphers such as Rivest Cipher 4 (RC4) are fast but present challenges in the form of a biased keystream along with weak key scheduling. For this reason, the use of RC4 alone is undesirable. In this paper, a hybrid scheme is discussed for encrypting digital images that uses RC4 and combines it with chaotic transformations, along with nonlinear cryptography, to help enhance the security of normal RC4. In the first stage of the proposed scheme, a secure 256-bit key is generated using a Password-Based Key-Derivation Function (PBKDF2) and HMAC-SHA256, which then is expanded using a novel scheme. The original Keystream Generation Algorithm used to generate the keystream in RC4 undergoes modifications. The keystream is further augmented using a Multiply-With-Carry (MWC) pseudo-random sequence to provide a more secure keystream while mitigating bias. The proposed scheme employs a unique process of encryption that employs pixel-wise substitution in a preliminary step using the PRESENT S-box, followed by a stage of spatial shuffling using Arnold’s Cat Map with the added step of diffusion to increase entropy and statistical randomness. All the results metrics demonstrate that the proposed scheme dilutes the known weaknesses presented in normal RC4, while simultaneously exhibiting strong secure image encryption capabilities, with desirable entropy, NPCR and UACI.

For recent decades, the increasing volume of multimedia data has been witnessed, and the data is required technical methods to assure the security for storage and transmission. Chaos-based encryption is one of promising approaches to keep large volume of data confidential. Most of chaos-based algorithms were proposed for single image encryption. Recently, several schemes were proposed for multiple image encryption, and all of them are designed to work in a single round of encryption. In addition, the dynamics of chaotic maps therein are stationary, so it does not provide advantage of uncertainty of chaotic orbits for the security. Moreover, a chaotic map being realized in digital platforms can produce a large number of bits, and so far those bits have not been used efficiently to encrypt larger volume of data. In this paper, a novel design of chaos-based multiple image encryption is proposed using the permutation-diffusion architecture for the first time. Any chaotic map can be employed for the proposed design. Chaotic dynamics are non-stationary by means of perturbation on state variables and control parameters in bit level. Amounts of perturbation are constructed from the coordinate of pixels and the content of plain images respectively in the pixel permutation and diffusion processes, so the proposed design provides the property of authentication. Values of chaotic state variables are represented in fixed-point number, and bits generated by chaotic maps are thoroughly exploited to encrypt multiple images at the same time. The specific example will demonstrate the effectiveness of the proposed design by means of the statistical and security analyses. The simulation results will show its resistance from the attacking method of differential analysis, and those are also compared with those of other existing algorithms.

A huge volume of image data is created every day, and it requires a fast and efficient encryption to keep them confidential. A chaos-based encryption is considered as the most suitable one for image encryption, and multiple image encryption is one of approaches to achieve the fast and efficient performance. However, the existing methods of multiple image encryption is with a lack of diffusion effect, inefficiency in using random number generated by chaotic map, and low speed. In this paper, a novel structure of chaos-based encryption is proposed to encrypt multiple images at the same time, in which the permutation and diffusion are integrated and they share the same chaotic map. The exclusive-OR operation is chosen for calculation and data manipulation during encryption. Therefore, the proposed structure allows to improve the efficiency and to reduce the time consumption for the encryption. In addition, the chaotic map is perturbed frequently and its dynamics is dependent on the content of images. It creates the dynamical session key, so the proposed structure can resist from the types of chosen-plaintext and chosen-ciphertext attacks. Two exemplar ciphers employing the proposed structure are demonstrated with the use of Logistic and Standard maps. The simulation results will be analysed and compared with those of existing methods to show the feasibility and effectiveness of the proposed structure of multiple image encryption.

This work presents a hybrid chaotic–cryptographic image encryption method that integrates a physical two-dimensional delta-kicked oscillator with a PBKDF2-HMAC-SHA256 key derivation function (KDF). The user-provided key material—a 12-character, human-readable key and four salt words—is transformed by the KDF into 256 bits of high-entropy data, which is then converted into 96 balanced decimal digits to seed the chaotic system. Encryption operates in the real number domain through a chaotic partition–permutation stage followed by modular diffusion. Experimental results confirm perfect reversibility, high randomness (Shannon entropy ≈7.9981), and negligible adjacent-pixel correlation. The method resists known- and chosen-plaintext attacks, showing no statistical dependence between plain and cipher images. Differential analysis yields NPCR≈99.6% and UACI≈33.9%, demonstrating complete diffusion. The PBKDF2-based key derivation expands the effective key space to 2256, eliminates weak-key conditions, and ensures full reproducibility. The proposed approach bridges deterministic chaos and modern cryptography, offering a secure, verifiable framework for protecting sensitive images.

Most of chaos-based cryptosystems utilize stationary dynamics of chaos for the permutation and diffusion, and many of those are successfully attacked. In this paper, novel models of the image permutation and diffusion are proposed, in which chaotic map is perturbed at bit level on state variables, on control parameters or on both. Amounts of perturbation are initially the coordinate of pixels in the permutation, the value of ciphered word in the diffusion, and then a value extracted from state variables in every iteration. Under the persistent perturbation, dynamics of chaotic map is nonstationary and dependent on the image content. The simulation results and analyses demonstrate the effectiveness of the proposed models by means of the good statistical properties of transformed image obtained after just only a single round.

This article presents a high-throughput image encryption algorithm implemented on an Artix-7 FPGA, which offers parallel processing, low latency, and real-time performance with a throughput of 0.8 Gbps, making it ideal for secure applications such as satellite imaging, surveillance, and medical diagnostics. The proposed method employs three chaotic systems: a 10D hyperchaotic system, an 8D hyperchaotic system, and a memristive coupled neural network (MCNN), to achieve a multi-layered encryption process that enhances confusion, diffusion, and key space complexity. The total key space of the algorithm is approximately , providing an extremely large search space that ensures robust protection against brute-force attacks. Performance results demonstrate excellent security properties, including high entropy values (), low pixel correlation coefficients (average ), and resistance to differential attacks. The FPGA-based implementation significantly outperforms software-only solutions in both speed and efficiency, validating its suitability for real-time, high-security image encryption scenarios.