Splicing Model and Hyper–Chaotic System for Image Encryption

This paper proposes a visually secure asymmetric image encryption scheme based on Rivest–Shamir–Adlemen (RSA) algorithm and hyperchaotic map. It combines the advantages of the RSA and chaos-based image encryption algorithms. First, to fully encrypt the image information, the plain image is encrypted into a cipher image by applying the row and column encryption algorithms. Second, the image secret key is converted into a ciphertext by utilizing the RSA algorithm to increase the security, and then the ciphertext is transformed into an image and permuted using the Arnold map to enhance the robustness of the embedded image. We then obtain the key cipher image. Finally, the cipher image and the key cipher image are embedded into a carrier image (CI) to obtain a visually secure image. It simultaneously achieves the image information security and image visually security. To further improve the security, the RSA keys management technique is applied and the initial conditions of the hyperchaotic map are updated in real time based on the plain image. In addition, the encryption scheme is suitable for multi-user image transmission with high security requirements and image transmission without the secure channel for key transmission. The simulation results and performance analysis validate the effectiveness, security and robustness of the proposed scheme.

Confusion and diffusion are two main concepts in cryptography that affect the quality of encryption and resistance to various attacks. Both of these concepts are influenced by the quality of the keystream used. Keystream generation needs to involve plain images as one way to bind sensitivity to plain images. But when it involves plain images directly, encryption security has negative side effects. So this research proposes to perform a diffusion operation with a logistic map on a plain image before generating the keystream. Not only using one keystream, the proposed method also uses three other keystreams and Arnold transform whose input parameters are processed by hash operations. Two keystreams are generated using the four-dimensional Lorenz system for the permutation of column and row image pixels. Next, sixteen Arnold transforms with different parameters are used for bit permutation. The last keystream is generated with a Henon map to carry out the diffusion stage two so that a cipher image is produced. Based on the testing results, the proposed method has satisfactory encryption results that are resistant to various attacks, especially brute force, statistical, and differential attacks.

Based on the permutation-diffusion architecture, this paper introduces a more sensitive chaotic image encryption scheme using breadth-first search and dynamic diffusion to enhance the security and sensitivity. In the permutation stage, the plain image is traversed by breadth-first search, and then the whole permutation is performed to obtain a shuffled sequence. Similarly, the diffusion key stream is rearranged by breadth-first search. Moreover, a dynamic diffusion method is proposed to encrypt the shuffled sequence in the diffusion stage, which can ensure that encrypting each pixel is related to all other pixels and can enhance the sensitivity of the cryptosystem. In each phase, the hyper-chaotic system in this scheme generates pseudorandom sequences. The simulation results and performance analysis show that the proposed scheme has excellent performances and high security in resisting brute-force attack, statistical attack and differential attack.

Image encryption become more significant since most of our data are communicated and stored as digital image form. To warrant high confidentiality, cipher image must be the produced in excellent quality to avoid any information leakage related to the original image. Since image has become one of the most used tools in information exchanges, large production and storage of cipher images are highly demanded, and this scenario could affect the production of high-quality cipher images. While most of existing encryption for images are for single image, processing multiple images simultaneously comes in handy as a fitting fast action to realize the convenience of encryption, storage, and transmission of multiple images. Inspired by those idea, we proposed a new chaotic encryption scheme using Sprott B hyperchaotic map. Using this scheme, two grayscale images are encrypted to produce a single cipher image. The encryption begins with the process of combining two images and encrypting the combined image using the hyperchaotic map. One cipher image will be produced representing and carrying information of the combination of the two images. Our experiments demonstrated significant enhancement offered by the scheme, while maintaining the quality of the recovered plain image. The proposed scheme yields cipher image with excellent quality in terms of noise-like visual of which the information of the images is concealed. While the proposed scheme satisfies the requirements of producing cipher images with excellent quality, it also achieves the credibility to decrypt the cipher image and restoring the plain image exactly similar to the original image.

Color image compression and encryption scheme based on compressive sensing and double random encryption strategy

Digital image transmission plays a very significant role in information transmission, so it is very important to protect the security of image transmission. Based on the analysis of existing image encryption algorithms, this article proposes a new digital image encryption algorithm based on the splicing model and 1D secondary chaotic system. Step one is the algorithm of this article divides the plain image into four sub-parts by using quaternary coding, and these four sub-parts can be coded separately. Only by acquiring all the sub-parts at one time can the attacker recover the useful plain image. Therefore, the algorithm has high security. Additionally, the image encryption scheme in this article used a 1D quadratic chaotic system, which makes the key space big enough to resist exhaustive attacks. The experimental data show that the image encryption algorithm has high security and a good encryption effect.

Image encryption based on chaotic maps is an important method for ensuring the secure communication of digital multimedia on the Internet. To improve the encryption performance and security of image encryption systems, a new image encryption algorithm is proposed that employs a compound chaotic map and random cyclic shift. First, a new hybrid chaotic system is designed by coupling logistic, ICMIC, Tent, and Chebyshev (HLITC) maps. Comparison tests with previous chaotic maps in terms of chaotic trajectory, Lyapunov exponent, and approximate entropy illustrate that the new hybrid chaotic map has better chaotic performance. Then, the proposed HLITC chaotic system and spiral transformation are used to develop a new chaotic image encryption scheme using the double permutation strategy. The new HLITC chaotic system is used to generate key sequences used in the image scrambling and diffusion stages. The spiral transformation controlled by the chaotic sequence is used to scramble the pixels of the plaintext image, while the XOR operation based on a chaotic map is used for pixel diffusion. Extensive experiments on statistical analysis, key sensitivity, and key space analysis were conducted. Experimental results show that the proposed encryption scheme has good robustness against brute-force attacks, statistical attacks, and differential attacks and is more effective than many existing chaotic image encryption algorithms.

Secured Compressive sensing of the images becomes one of the essential issues in multimedia applications. In the recent times, encryption in compressive sensing is achieved via the use of multiple one dimensional chaotic system (1D chaotic) and hyper-chaotic system (HC). However, the security of the system still needs to be improved. To solve this issue, novel encrypted compressive sensing of images based on Fractional order hyper chaotic Chen system and DNA operations is proposed in this paper. The basic idea is to introduce a new algorithm which provides compression rate below the Nyquist rate along with increased security by jointly using Fractional order hyper chaotic chen system and DNA operations for image encryption. The encryption algorithm combines Fractional order hyperchaotic chen system and DNA operations. Fractional order hyperchaotic chen system has high randomness and rich dynamic phenomena which enhance the encryption and the algorithm efficiency is further increased by DNA operations.4-Dimensioanal Fractional order hyper chaotic chen system is used to generate the measurement matrix. Compressive sensing measurements are converted to a stream of binary digits and the correlation between the adjacent bits is further reduced through global scrambling. The DNA operations are performed on the scrambled binary sequences and hyper chaotic sequences, which increases the algorithm efficiency. The results of the experiments accomplish that the proposed encryption method is extremely sensitive to small changes in secret keys, shows good performance in histogram analysis, correlation analysis, Information Entropy and is very sensitive to a bit change in an input image. The Block Compressive sensing (BCS) reconstruction algorithms are used to validate the proposed encryption method. In the proposed method, experimental analysis are performed on different images of size 512 × 512 which are divided in to blocks of size 32 X 32. The reconstruction analysis is performed with different subsampling rates of 0.1, 0.2, 0.3, 0.4 and 0.5.The results depicted that the proposed method maintains the robustness and reconstruction quality of Compressive sensing with enhanced encryption.

Chaos-based encryption has emerged as a promising approach for securing digital images, particularly in sensitive domains such as medical imaging. However, existing chaos-based encryption algorithms often suffer from design flaws and the use of weak chaotic maps that exhibit limited chaotic ranges and vulnerability to signal estimation. These limitations result in insufficient key space, reduced resistance to statistical and differential attacks, and inefficiency in real-time applications. To address these challenges, this study introduces a novel 1D Cosine-Exponential (1DCE) map, a hypersensitive chaotic map characterized by enhanced chaotic behavior and robustness. Leveraging the 1DCE map, we propose a real-time image encryption algorithm, termed DCEIES, which incorporates a cross-row-column encryption strategy to significantly improve both encryption speed and security. The DCEIES algorithm also integrates a novel image sensitivity function that detects any alterations in the plain image, rendering the cryptosystem resistant to differential attacks. While the DCEIES algorithm is versatile and applicable to various types of images, its design is particularly optimized for medical imaging, where high pixel correlations and sensitivity to input changes are critical. Extensive simulations and security analyses demonstrate that the DCEIES algorithm outperforms state-of-the-art encryption algorithms in terms of high security and computational efficiency. The results highlight the potential of the DCEIES algorithm for real-time medical image encryption.

In view of most of the current image encryption algorithm based on chaotic sequences, the permutation and diffusion procedures are completely independent, use different state variables, and the key stream is completely dependent on the key algorithm, namely, constant algorithm key words of different plaintexts are encrypted, using the key flow is the same, so it is difficult to resist the plaintext attack or selective plaintext attack. This paper has designed a dynamic encryption algorithm based on hyperchaotic system. In this paper, the system is pre-processed to obtain the ideal chaotic sequence which has the better randomness, and the dynamic alternative sequence associated with the plain image is constructed, the secret key related to the dynamic sequence is created, which is used for the permutation and diffusion processes of digital image. In the proposed algorithm, if plain image or the chaotic sequences has minor changes, it will result an entirely different key stream. Experimental simulations and a lot of cryptanalysis have been carried out, the results prove the superior security and high efficiency of the scheme.

Chaotic systems are evidently very sensitive to slight perturbations in their algebraic structures and initial conditions, which can result in unpredictability of their future states. This characteristic has rendered them very useful in modelling and design of engineering and non-engineering systems. Using the Burke-Shaw chaotic system as a reference template, a special case of a novel 4-D hyperchaotic system is proposed. The system consists of 10 terms and 9 bounded parameters. In this paper, after the realization of a mathematical model of the novel system, we designed an autonomous electronic circuit equivalent of the model and subsequently proposed an improved adaptive finite-time stabilizing controllers which incorporates some augmented strength coefficients in the derived controller structures. These augmented coefficients greatly constrained transient overshoots and resulted in a faster convergence time for the controlled trajectories of the novel system. This novel system is suitable for application in the modelling and design of information security systems such as image encryption and multimedia security systems, due to its good bifurcation property.

In this paper, a novel image encryption algorithm based on a new permutation scheme and DNA operations are introduced. In our algorithm, SHA 256 and DNA hamming distance participate in the generation of the initial conditions of the 4D chaotic system, which can associate the encryption system with the original image. In the permutation process, based on the adjustment process of the IAVL (improved balanced binary tree), a new scrambling algorithm is constructed. Then the dynamic block coding rules are designed, in which different image blocks have different coding rules. In the diffusion process, a new diffusion algorithm with intra-block and inter-block is proposed to perform DNA operations on the intermediate encryption result and the key matrix. In the security analysis, the key space of the encryption system is 2 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">933</sup> and the information entropy is about 7.9973. In addition, the NPCR and UACI in the differential attack test are close to the ideal values of 99.6094% and 33.4653%. To further prove the security of the encryption algorithm, the Irregular deviation, Maximum deviation, Energy, Contrast, and Homogeneity tests are introduced into the analysis. Experimental results illustrate that the encryption scheme can against multiple illegal attacks like statistical, brute-force and differential attacks.

Internet is an important part in the daily life of people in many ways, which allows the people in any corner of the world to share all types of information. Image encryption is used to transmit sensitive multimedia information in unsecured networks to provide high degree of confidentiality. In this paper, a new image encryption method is proposed based on novel implementation of pixel scan, utilizing the Knight’s Travel Path, and true random number. The Knight’s travel path is a pattern in which the path of a Knight around a chess board is taken without revisiting any node. This travel path pattern is used to permute the pixel positions of the original image to obtain the scrambled image. The scrambled image is further XORed with the random key numbers to get the cipher image. To change the pixel values of the scrambled image, true random numbers are generated from the amplitude values of a chosen noise audio file. Decryption is performed to confirm the reception of the sent image. The proposed method resists the statistical, differential, and entropy attacks significantly which have been demonstrated with various standard images.

Cryptanalyzing an image encryption scheme based on hybrid chaotic system and cyclic elliptic curve

With the popularity of social networks and the increase of cloud platform applications, service computing has also developed. Therefore, the protection of information even privacy uploaded to the cloud server has become critical. Recently, some researchers have proposed encryption schemes of visual meaningful image by using compressive sensing. However, these schemes generally cannot hide the large-size of plain image into the small-size of cover image and cannot recover the original plain image lossless. To solve above problems, this paper proposed a visually meaningful image encryption scheme based on lossless compression set partitioning in hierarchical trees (SPIHT) coding. The sender encrypts the plain image into the cipher image through the proposed encryption scheme, and then uploads the cipher image to the cloud server which is assumed as semi-honest trusted. Authorized receiver can completely decrypt the plain image after downloading the cipher image. In addition, even if the cipher image is attacked by attacker in the cloud server, the final decrypted image is still readable. Experimental results show that the proposed scheme is not only completely reversible and can hide the large-size of plain image into the small-size of cover image, but also superior to other schemes in visual quality and anti-attack performance.