Multiple-image Encryption Research Articles

Encrypting Multiple Images With an Enhanced Chaotic Map

A multiple-image encryption scheme based on an enhanced chaotic map is proposed. This scheme combines multiple grayscale images into three planes. An amplified sine map is used to generate a dynamic permutation table and a chaotic sequence. The initial parameters of the amplified sine map are obtained from an elliptic curve coordinate, computing using elliptic curve point multiplication between the input image hash value and the seed value of an elliptic curve. The dynamic permutation table performs cyclic shift transformation on the input image, diffusing it horizontally and vertically. The diffused image is converted to a cipher image through an XOR operation with the chaotic sequence generated by the amplified sine map. Using an amplified sine map provides larger key space, more extensive chaotic range, more extensive control parameters, better sensitive initial values and enhanced security against cryptanalysis. The experiment results indicate that the proposed scheme is fast, secure, efficient and can resist certain cryptographic attacks. Compared to other recent schemes, the proposed scheme is shown to be secure and efficient.

Compressed optical image encryption in the diffractive-imaging-based scheme by input plane and output plane random sampling

The successful recovery of the plaintext in the simplified diffractive-imaging-based encryption (S-DIBE) scheme needs to record one intact axial intensity map as the ciphertext. By aid of compressive sensing, we propose here a new image encryption approach, referred to as compressed DIBE (C-DIBE), which allows further compression of the intensity map. The plaintext is sampled before being sent to DIBE. Afterwards, the intensity map recorded by the CCD camera is also processed by such sampling operation to generate the ciphertext. For decryption, we first obtain the sparse plaintext using the proposed phase retrieval algorithm, and then reobtain the primary plaintext from it via compressive sensing. Numerical results show that a proper proportion of the intensity map (e.g. 50%) is enough to totally recover a grayscale image. We achieve multiple-image encryption by space multiplexing without enlarging the size of the ciphertext. The robustness of C-DIBE against brute-force attack evidently outperforms S-DIBE due to the extended key space. Numerical simulation has been presented to confirm the proposal.

Multiple RGB images encryption algorithm based on elliptic curve, improved Diffie Hellman protocol

Multiple RGB images encryption algorithm based on elliptic curve, improved Diffie Hellman protocol

Interference-based multiple-image encryption and authentication via lateral shift multiplexing and sparsification

We report a novel optical method of interference-based multiple-image encryption and authentication via lateral shift multiplexing and sparsification. We encode multiple original images into two ciphertexts only containing partial information of the multiple images when the secret key generated randomly is laterally movable within a predefined interval, and we analytically derive the two other keys of each original image. Information discrimination for each original image as well as its silhouette is still prohibited in spite of the utilization of one, two, three, or even four masks for decryption. The three secret keys of each original image significantly improve the security of the proposed method, and binary amplitude masks are included in the decryption and authentication procedure. Moreover, the proposed scheme completely eliminates the cross-talk problem and destroys any high correlation between the plaintexts and ciphertexts. Numerical simulations are executed to prove the effectiveness and security of this scheme.

Novel Multiple-Image Encryption Scheme Based on Coherent Beam Combining and Equal Modulus Decomposition

In our research, we propose a novel asymmetric multiple-image encryption method using a conjugate Dammann grating (CDG), which is based on the coherent beam combining (CBC) principle. The phase generated by the Dammann grating (DG) beam splitting system is processed and added to the image to be encrypted, and then, the ciphertexts and keys are generated by equal modulus decomposition (EMD). Decryption is to combine the beams through the CDG and collect the combined images in the far field. The proposed encryption scheme is flexible and thus extendable. CDG structure parameters, such as one period length of CDG, can be used as encryption key for the increase of the complexity. The Fresnel diffraction distance can also be used as an encryption key. The power of the combined beam is stronger than that of the single beam system, which is convenient for long-distance transmission and also easy to detect. Simulation results show that the proposed method is effective and efficient for asymmetric multiple-image encryption. Sensitivity analysis of CDG alignment has also been performed showing the robustness of the system. The influence of occlusion attack and noise attack on decryption are also discussed, which proves the stability of the system.

Research on multiple-image encryption mechanism based on Radon transform and ghost imaging

In the process of multiple-image encryption, there are some problems such as low reconstruction accuracy, easy cross-talk, and poor robust performance. To solve these problems, a multiple-image encryption algorithm based on Radon transform and ghost imaging is proposed. Radon transform is applied to the encryption system of ghost imaging. The Cartesian coordinates of the two-dimensional images are firstly converted to the polar coordinates. Then, the Radon transform is fully used to obtain the projection of digital images at arbitrarily given angles. By adjusting the projecting angle interval, the spatial division multiplexing is used to realize the multiple-image encryption. By the numerical simulations and optical experiments, the feasibility of the proposed encryption system is verified. The results show that the proposed system not only reduces the amount of data transmission, but also improves the precision of the reconstructed image and the robustness of the encryption system.

Ghost imaging-based optical cryptosystem for multiple images using integral property of the Fourier transform* *Project supported by the Natural Science Foundation of Shanghai, China (Grant No. 18ZR1425800) and the National Natural Science Foundation of China (Grant Nos. 61875125 and 61775140).

A novel ghost imaging-based optical cryptosystem for multiple images using the integral property of the Fourier transform is proposed. Different from other multiple-image encryption schemes, we mainly construct the modulation patterns related to the plaintext images to realize the encrypted transmission of multiple images. In encryption process, the first image is encrypted by the ghost imaging encryption scheme, and the intensity sequence obtained by the bucket detector is used as the ciphertext. Then modulation patterns of other images are constructed by using the integral property of the Fourier transform and used as the keys. Finally, the ciphertext and keys are transmitted to the receiver to complete the encryption process. During decryption, the receiver uses different keys to decrypt the ciphertext and gets different plaintext images, and decrypted images have no image aliasing problem. Experiments and simulations verify the feasibility, security, and robustness of the proposed scheme. This scheme has high scalability and broad application prospect, which provides a new idea for optical information encryption.

Optical multiple-image authentication and encryption based on phase retrieval and interference with sparsity constraints

An optical multiple-image authentication and encryption method based on phase retrieval algorithm (PRA) in the Fresnel domain and interference with sparsity constraints is proposed. In our proposed method, sparse phase and space multiplexing technique are respectively introduced to authentication and encryption for multiple-image. Each target image is respectively encrypted into two phase-only masks, which contain the phase data generated from three binary images by applying PRA in the Fresnel domain and need to be verified before used for decryption. That the target images are respectively reconstructed by using different decryption keys in the proposed method increases the security of the cryptosystem. Numerical simulation shows that the proposed method has high multiplexing capacity and security.

A novel multiple color image encryption scheme based on algebra M(2, F2[u]/〈u8〉) and chaotic map

The substance security of computerized images ends up being a huge issue for researchers and architects. Thus, it is important to obscure and conceal image data before an impart over the web for security. Due to the operational strength of the matrix algebra M(2,F2[u]〈u8〉) and a unique attempt on a 4D chaotic map, this study recommends novel multiple colored image encryption techniques. This technique is applied in two stages. Initially, a double permutation model is built to permute a group of images, and hence row and column permutations are incorporated. Finally, chaotic sequences are produced by the 4D chaotic system to perform the exclusive OR operation on permuted images and chaotic successions. The proposed cryptosystem is assessed by using different analyses. The outcomes of our investigation support the fact that the proposed technique is satisfying in terms of high security and better adequacy when contrasted with the present algorithms.

Research on multiple-image encryption scheme based on joint power spectral division multiplexing and ghost imaging

Since there are problems of easy cross-talk, large ciphertext transmission and low security in the process of multiple-image encryption, in order to solve these problems, a multiple-image encryption algorithm based on joint power spectral division multiplexing and ghost imaging (GI) is proposed. The joint transform correlator is combined with GI to realize ‘one encryption to one key’, which improves the security of the encryption system. Joint power spectrum (JPS) is compressed by the iterative restoration algorithm to reduce the transmissions of ciphertext. The joint power spectral division multiplexing is used, and the optimized phase mask is linearly superposed. The JPS of each channel has different positions on the spectrum plane, and then the non-crosstalk superposition is realized by window filtering. In this paper, the security, robustness, and encryption capacity of the encryption system are verified by numerical simulation.

Multiple-image encryption based on Toeplitz matrix ghost imaging and elliptic curve cryptography

To improve the security of encryption systems, we propose a multiple-image encryption method via Toeplitz matrix ghost imaging and elliptic curve cryptography. Specifically, each unencrypted image is firstly compressed using wavelet transformation. Compressed images are merged into a single image via spatial multiplexing technology. Then, based on the ghost imaging, the phase mask matrix of the speckle sequence is modulated into a random Toeplitz matrix, through the logistic mapping sequence to achieve the encryption of the combined image. The detection data of all images is obtained through a bucket detector. Finally, the obtained detection data is encrypted twice using an elliptic curve asymmetric cryptographic algorithm to obtain the final ciphertext. In the decryption process, images are recovered using elliptic curve, compressive sensing technology and inverse wavelet transformation. This method provides strong security features for encryption systems. The basic principle of the encryption scheme is analyzed theoretically, and the security and robustness of the proposed method are verified by numerical simulation.

An efficient dual-layer cross-coupled chaotic map security-based multi-image encryption system

This paper proposes an effective image encryption method to encrypt several images in one encryption process. The proposed encryption scheme differs from the current multiple image encryption schemes because of their two-layer cross-coupled chaotic map-based permutation-diffusion operation. Block-shuffling, left–right (L–R) flipping and then bit-XOR diffusion operations are carried out in the first layer using one set of cross-coupled chaotic map. Block-shuffling, up–down (U–D) flipping and then bit-XOR diffusion operations are performed with another set of cross-coupled chaotic maps in the second layer. The two different layers of permutation-diffusion make the proposed algorithm more efficient than the existing multi-image encryption algorithms. Moreover, the combination of block-based shuffling and flip operation decreases the algorithm’s computational complexity, which means enhancing the time efficiency of the algorithm. In cross-coupling operation, the use of a single fixed-type one-dimensional chaotic map-piece-wise linear chaotic map (PWLCM) makes the algorithm efficient both in hardware and in software. PWLCM’s initial values and system parameters (keys) are generated by means of the hash values of original images that resist the algorithm against the attacks of chosen-plaintext and known-plaintext. Results of simulation and comparative security analysis reveal that the suggested scheme is more effective in encryption and resists better against all widely used attacks.

Multiple-image encryption algorithm based on the 3D scrambling model and dynamic DNA coding

Lots of digital images from different fields distributed in Internet are exposed to various risks, such as the content leakage, illegal access and use. To solve the problems of weak security, insufficient encryption capacity and low encryption efficiency, this paper proposes a multiple-image encryption (MIE) algorithm based on the three-dimensional (3D) scrambling model and dynamic DNA coding. Firstly, this paper designs a generalized Zigzag transformation and establishes the 3D scrambling model based on the dimensionality reduction; secondly, multiple plain images are combined into 3D image cube, and the scrambled images can be obtained by the established 3D scrambling model; thirdly, the chaotic sequences are used to perform the dynamic DNA coding and DNA operations on the scrambled images; finally, dynamic DNA decoding operation is performed to obtain the final encryption image. Experimental results and algorithm analyses show that the proposed algorithm has the advantages of large encryption capacity, high encryption efficiency, large key space, high key sensitivity, strong ability to resist the statistical attack, the brute-force attack, the chosen-plaintext attack, etc. Therefore, the proposed algorithm can play a great role in the security of batch image data with high security requirements and large data volume.

A Symmetric Key Multiple Color Image Cipher Based on Cellular Automata, Chaos Theory and Image Mixing

The transmission of significant masses of sensitive and secret images over a public network is inevitable, and demands effective tools and technology to safeguard and conceal the data. In this paper, a symmetric multiple color image encryption technique is proposed by adopting a dual permutation and dual substitution framework. Firstly, the input images are combined into a large image and then segmented into many small and equal-sized pure-image elements. Secondly, using the elementary cellular automata Rule-30, these pure-image elements are permuted to obtain mixed-image elements. Thirdly, second-level permutation is undertaken on the mixed-image elements by applying zigzag pattern scanning. Fourthly, pixel values are substituted by employing the circular shift method; subsequently, second-level pixel substitution is realized through using chaotic random sequences from a 2D logistic map. Finally, the big encrypted image is segmented into smaller encrypted images. Additionally, the keys are calculated from the input images to attain input sensitivity. The efficiency of this method is quantified, based on the unified average changing intensity (UACI), information entropy, number of pixels change rate (NPCR), key sensitivity, key space, histogram, peak signal-to-noise ratio (PSNR) and correlation coefficient (CC) performance metrics. The outcome of the experiments and a comparative analysis with two similar methods indicate that the proposed method produced high security results.

Parallel Binary Image Cryptosystem Via Spiking Neural Networks Variants.

Due to the inefficiency of multiple binary images encryption, a parallel binary image encryption framework based on the typical variants of spiking neural networks, spiking neural P (SNP) systems is proposed in this paper. More specifically, the two basic units in the proposed image cryptosystem, the permutation unit and the diffusion unit, are designed through SNP systems with multiple channels and polarizations (SNP-MCP systems), and SNP systems with astrocyte-like control (SNP-ALC systems), respectively. Different from the serial computing of the traditional image permutation/diffusion unit, SNP-MCP-based permutation/SNP-ALC-based diffusion unit can realize parallel computing through the parallel use of rules inside the neurons. Theoretical analysis results confirm the high efficiency of the binary image proposed cryptosystem. Security analysis experiments demonstrate the security of the proposed cryptosystem.

A Robust and Fast Image Encryption Scheme Based on a Mixing Technique

This paper introduces a new image encryption scheme using a mixing technique as a way to encrypt one or multiple images of different types and sizes. The mixing model follows a nonlinear mathematical expression based on Cramer’s rule. Two 1D systems already developed in the literature, namely, the May-Gompertz map and the piecewise linear chaotic map, were used in the mixing process as pseudo-random number generators for their good chaotic properties. The image to be encrypted was first of all partitioned into N subimages of the same size. The subimages underwent a block permutation using the May-Gompertz map. This was followed by a pixel-based permutation using the piecewise linear chaotic map. The result of the two previous permutations was divided into 4 subimages, which were then mixed using pseudo-random matrices generated from the two maps mentioned above. Tests carried out on the cryptosystem designed proved that it was fast due to the 1D maps used, robust in terms of noise and data loss, exhibited a large key space, and resisted all common attacks. A very interesting feature of the proposed cryptosystem is that it works well for simultaneous multiple-image encryption.

Multiple-image encryption based on light-field imaging and gravity model

A new multiple-image encryption method based on a light-field imaging system and the gravity model is presented in this paper. An inverse process of light-field imaging was used for multiple-image encryption. The method first combined multiple images into one light-field image. It was then encrypted using the gravity model, which further improved the security. The structural parameters of the light-field imaging system and the different objective distances of each original image could be used as part of the secret keys. A refocusing reconstruction algorithm for the light-field image was used in the decryption process. Experiments and analyses have shown that the proposed scheme could easily be accessed and provides a large key space and high sensitivity in the key space. Furthermore, it is robust against occlusion attacks. Compared with the repeated use of gravity model alone, the proposed method offers enhanced statistical properties and efficiency benefits. The proposed encryption can be achieved by a computational way, which can eliminate the negative effects of hardware limitations and aberrations.

Multiple-image encryption based on cascaded gyrator transforms and high-dimensional chaotic system

In order to increase encryption capacity and improve transmission efficiency, this paper investigates an encryption scheme for multiple-image based on cascaded gyrator transforms and high-dimensional chaos. Firstly, each plainimage is converted into a real matrix through modulation, quaternion gyrator transform and sharing. The real matrices are connected in turn by plural coding and gyrator transforms. During the process of cascade, phase truncation and preservation operations are performed. The phase of the preceding transformation is modulated by that of the latter complex matrix to enhance security. Followed by splicing and scrambling, a real-valued ciphertext can be obtained. At the receiver end, all the plaintext images can be restituted by the reverse operation of the encryption process using the authorized keys. The adoption of high-dimensioanl chaos and Kronecker product further guarantees the security of the cryptosystem. The numerical results performed on 300 color images have demonstrated that the average PSNR of correctly decrypted images is up to 303.9939 dB, the NMSE is as low as 2.8024 × 10−28 and SSIM is equal to 1.0000. The analysis of sensitivity, statistical characteristic and robustness proves the feasibility and relibility of the proposed encryption scheme.

Multi-image and color image encryption via multi-slice ptychographic encoding

Multi-slice ptychography is a diffractive imaging technique that can reconstruct the information of a 3-D object from its diffraction intensities. In this article, we propose a multi-slice ptychographic encoding method for the encryption of multiple and color images. Full-phase images to be encrypted together with inserted phase keys are transformed into diffraction intensities (i.e., cipher texts) via multi-slice ptychographic encoding and double random phase encoding. The multi-slice ptychographic encoding refers to the process of using ptychographic scanning and recording to encrypt a multi-slice object that is composed of secret images and inserted phase keys. During decryption, an iterative phase retrieval algorithm is modified. The feasibility, robustness and security of the proposed method are analyzed. Numerical simulation results show that the proposed method can achieve high-quality decryption, and has high security and robustness against noise, compression, and occlusion.

Modified Gerchberg–Saxton (G-S) Algorithm and Its Application

The Gerchberg–Saxton (G-S) algorithm is a phase retrieval algorithm that is widely used in beam shaping and optical information processing. However, the G-S algorithm has difficulty obtaining the exact solution after iterating, and an approximate solution is often obtained. In this paper, we propose a series of modified G-S algorithms based on the Fresnel transform domain, including the single-phase retrieval (SPR) algorithm, the double-phase retrieval (DPR) algorithm, and the multiple-phase retrieval (MPR) algorithm. The analysis results show that the convergence of the SPR algorithm is better than that of the G-S algorithm, but the exact solution is not obtained. The DPR and MPR algorithms have good convergence and can obtain exact solutions; that is, the information is recovered losslessly. We discuss the security advantages and verification reliability of the proposed algorithms in image encryption. A multiple-image encryption scheme is proposed, in which n plaintexts can be recovered from n ciphertexts, which greatly improves the efficiency of the system. Finally, the proposed algorithms are compared with the current phase retrieval algorithms, and future applications are discussed. We hope that our research can provide new ideas for the application of the G-S algorithm.