Optimized Chaotic encrypted image based on continuous raster scan method

In the last decade, the communication of images through the internet has increased. Due to the growing demands for data transfer through images, protection of data and safe communication is very important. For this purpose, many encryption techniques have been designed and developed. New and secured encryption schemes based on chaos theory have introduced methods for secure as well as fast communication. A modified image encryption process is proposed in this work with chaotic maps and orthogonal matrix in Hill cipher. Image encryption involves three phases. In the first phase, a chaotic Henon map is used for permuting the digital image. In the second phase, a Hill cipher is used whose encryption key is generated by an orthogonal matrix which further is produced from the equation of the plane. In the third phase, a sequence is generated by a chaotic tent map which is later XORed. Chaotic maps play an important role in the encryption process. To deal with the issues of fast and highly secured image processing, the prominent properties of non-periodical movement and non-convergence of chaotic theory play an important role. The proposed scheme is resistant to different attacks on the cipher image. Different tests have been applied to evaluate the proposed technique. The results of the tests such as key space analysis, key sensitivity analysis, and information entropy, histogram correlation of the adjacent pixels, number of pixel change rate (NPCR), peak signal to noise ratio (PSNR), and unified average changing intensity (UCAI) showed that our proposed scheme is an efficient encryption technique. The proposed approach is also compared with some state-of-the-art image encryption techniques. In the view of statistical analysis, we claim that our proposed encryption algorithm is secured.

Chaos and compressive sensing based novel image encryption scheme

The security and confidentiality of medical images are of utmost importance due to frequent issues such as leakage, theft, and tampering during transmission and storage, which seriously impact patient privacy. Traditional encryption techniques applied to entire images have proven to be ineffective in guaranteeing timely encryption and preserving the privacy of organ regions separated from the background. In response, this study proposes a specialized and efficient local image encryption algorithm for the medical field. The proposed encryption algorithm focuses on the regions of interest (ROI) within massive medical images. Initially, the Laplacian of Gaussian operator and the outer boundary tracking algorithm are employed to extract the binary image and achieve ROI edge extraction. Subsequently, the image is divided into ROI and ROB (regions outside ROI). The ROI is transformed into a row vector and rearranged using the Lorenz hyperchaotic system. The rearranged sequence is XOR with the random sequence generated by the Henon chaotic map. Next, the encrypted sequence is arranged according to the location of the ROI region and recombined with the unencrypted ROB to obtain the complete encrypted image. Finally, the least significant bit algorithm controlled by the key is used to embed binary image into the encrypted image to ensure lossless decryption of the medical images. Experimental verification demonstrates that the proposed selective encryption algorithm for massive medical images offers relatively ideal security and higher encryption efficiency. This algorithm addresses the privacy concerns and challenges faced in the medical field and contributes to the secure transmission and storage of massive medical images.

Due to easy and simple implementation, normally single 1-D chaotic maps like logistic and sine maps are employed in multimedia data encryption. However, data encrypted through a single chaotic map does not provide better security in terms of resistance against various attacks. In this paper, 2D Henon chaotic map and skew tent map are deployed in the design of an efficient chaos-based image encryption algorithm. To confuse the relationship between plaintext and ciphertext images, both chaotic maps play a key role in the permutation and diffusion mechanism. In the confusion stage, firstly, the Henon chaotic map generates two different chaotic sequences, which are further applied in row and column permutation of plaintext image. The pixel values diffusion is produced by unimodal skew tent map via XOR operations. In the last stage of encryption algorithm, Hussain's substitution box is used to substitute each pixel into a new random pixel. Extensive security analysis and resistance to statistical attack prove the security of anticipated scheme.

Security of image data is essential during communication from various security attacks. This paper proposed a new technique for RGB color image encryption and decryption by the combination of shuffling and masking. The chaotic Baker map is used for first layer of image encryption by randomizing the pixels of each components of color image such as red, green and blue and then applying the diffusion process i.e. fractional dual random phase masks (FDRPM) technique which is applied on each component to increase the security level of given method. The order of Discrete Fractional Fourier Transform (DFRFT) act as a key for the process which provides extra degree of security to the proposed system. Matlab simulations are performed to check the security robustness of proposed scheme. Performance of proposed scheme is verified by noise analysis such as mean square error (MSE) and various differential analysis such as Unified Average Change Intensity (UACI) and Number of Pixels Change Rate (NPCR). Results of various analysis shows that the novel proposed encryption technique shows high efficiency and security for color images.

An image encryption scheme based on new spatiotemporal chaos

Exponentially increasing multimedia data over the internet raises concerns over its security. In the current work, we present a new technique for encrypting digital images based upon the pixel shuffling combined with changing pixel values using 128-bit secret key using henon chaotic map. Chaotic maps are characterized by their high sensitivity towards the initial parameters, which makes it a natural choice for developing a dynamic permutation matrix or as it is mostly called, permutation map. So we used chaotic Henon map in order to dynamically generate the permutation matrix. The initial parameters of the chaotic map and the secret key for changing the pixel values are derived from an external secret key. Horizontal and vertical permutations are used to perform pixel shuffling. Shuffling is used to destroy the correlation among the neighbour or adjacent image pixels, also it helps in increasing diffusion in the image. The proposed scheme is tested against a series of tests to measure its performance. Results of such tests indicate that the proposed algorithm is highly sensitive towards the encryption key and showed high resistance against various brute-force or statistical attacks.

Image encryption has been an attractive research field in recent years. The chaos-based cryptographic algorithms have suggested some new and efficient ways to develop secure image encryption techniques. This paper proposes a novel image encryption scheme, which is based on the chaotic tent map. Image encryption systems based on such map show some better performances. Firstly, the chaotic tent map is modified to generate chaotic key stream that is more suitable for image encryption. Secondly, the chaos-based key stream is generated by a 1-D chaotic tent map, which has a better performance in terms of randomness properties and security level. The performance and security analysis of the proposed image encryption scheme is performed using well-known ways. The results of the fail-safe analysis are inspiring, and it can be concluded that the proposed scheme is efficient and secure.

In open network, it is important to keep sensitive information secure from becoming vulnerable to unauthorized access. Encryption is used to ensure high security for Images. Chaos has been widely used for image encryption for its different features. There are many chaos based encryption techniques. Most of the proposed discrete chaotic cryptographic approaches are based on stream or block cipher schemes. If these two schemes are combined the security level is improved. Novel image encryption is proposed based on combination of pixel shuffling. Chaos is used for expand diffusion & confusion in image. Chaotic maps gives advantages of large key space and high level security. We survey exiting work which uses different techniques for image encryption and analyse them with respect to various parameters. To evaluate security & performance, key space analysis, correlation coefficient, histogram, information entropy, NPCR, UACI etc. will be studied.

The main purpose of the proposed image encryption (IE) method is to enhance various security characteristics to protect sensitive images on the internet. In the literature, chaotic maps are preferred for image encryption because of their high randomness and sensitivity to initial parameter values. Therefore, metaheuristic algorithms have been utilized to fine-tune the parameters. In this research, we have employed the metaheuristic Lyrebird optimization (LO) algorithm to fine-tune the chaotic map parameters. The LO algorithm is chosen over other algorithms due to its better exploration and exploitation rate to search for the best solution. The LO algorithm searches for the best parameter value based on the objective function. This research involves the formulation of a multi-objective function that incorporates numerous security parameters, namely, entropy and correlation coefficient (CC), to improve the security attributes of the IE model. The proposed IE model has two steps. In the first step, a random key is generated to transform the pixels of the secret image, whereas in the second step, the image pixels are shuffled based on the shuffling index values to reduce the correlation among the neighboring pixels. In both steps, we have used the chaotic logistic map. The proposed IE is evaluated against statistical and differential attacks on the standard dataset by considering the various images and their different resolutions. The uniform distribution of the histogram of the encrypted images is validated using the chi-square test. Besides that, entropy analysis shows that the average entropy value is 7.9973, 7.9993, and 7.9998 for 256x256, 512x512, and 1024x1024 image resolutions. The average CC and SSIM are near zero value. The average NPCR value (>0.9969) is near the 1 value. Finally, the comparative analysis based on entropy, CC, and NPCR parameters shows that the proposed IE model outperforms the existing models.

Exploiting one-dimensional exponential Chebyshev chaotic map and matching embedding for visually meaningful image encryption

In recent years, encryption technology has been developed quickly and many image encryption methods have been put forward. Chaos based image encryption technique is a new encryption technique for images. It utilizes chaos random sequence to encrypt image, which is an efficient way to deal with the intractable problem of fast and highly secure image encryption. However, the Chaos based image encryption technique has some deficiencies, such as the limited accuracy problem. This paper researches on the chaotic encryption, DES encryption and a combination of image encryption algorithm, and simulate these algorithms, through analysis of the algorithm to find the gaps. And on this basis, the algorithm has been improved. The new encryption scheme realizes the digital image encryption through the chaos and improving DES. Firstly, new encryption scheme uses the Logistic chaos sequencer to make the pseudo-random sequence, carries on the RGB with this sequence to the image chaotically, then makes double time encryptions with improvement DES, displays they respective merit. Theoretical analysis and the simulation indicate that this plan has the high starting value sensitivity, and enjoys high security and the encryption speed. In addition it also keeps the neighboring RGB relevance close to zero. The algorithm can be used in the actual image encryption.

At present times the topic of Chaos gain a lot of attention for the encryption/decryption methodology, yet we didn’t settled to get a good difference between conventional counterparts. Several chaotic maps can be considered sensitivity dependence to seed values. Taking into consideration for this property, In this paper, the author have presented an image encryption technique employing a 2-dimensional chaotic Henon map, initially it implemented the confusion scheme using chaotic sequence obtained by several iterations using chaotic map approach. In the subsequent stage Edge Maps, generated by edge detection filters and binary bit plane decomposition is applied to perform further confusion using a bit-xor operation to get a cipher image. It is more secure and robust, experimental analysis and simulation is performed to get required results which better revealed that the encrypted images are secured and tolerant to different attacks.

Image encryption technology has been applied in many fields and is becoming the main way of protecting the image information security. There are also many ways of image encryption. However, the existing encryption algorithms, in order to obtain a better effect of encryption, always need encrypting several times. There is not an effective method to decide the number of encryption times, generally determined by the human eyes. The paper proposes an image encryption algorithm based on chaos and simultaneously proposes a balanced pixel algorithm to determine the times of image encryption. Many simulation experiments have been done including encryption effect and security analysis. Experimental results show that the proposed method is feasible and effective.

A robust and secure chaotic standard map based pseudorandom permutation-substitution scheme for image encryption