Proposed Encryption Method Research Articles

Opposition Based Joint Grey Wolf-Whale Optimization Algorithm Based Attribute Based Encryption in Secure Wireless Communication

At present times, medical image security becomes a hot research topic in the healthcare sector. This paper presents an efficient lightweight image encryption model based on the Dynamic key generating Attribute based encryption (ABE) method with Opposition based joint Grey Wolf-Whale Optimization Algorithm (OjGW-WOA). The proposed encryption method undergoes certain pre-encryption steps like rotation and random column addition steps. Once the pre-encryption steps are done, ABE with OjGW-WOA is incorporated, where the optimal key is generated based on entropy value. In addition, the oppositional based learning concept is introduced to enhance the convergence rate and searching process of GWO and WOA algorithms. Next, the proposed encryption method is designed with a dynamic key generating model that generates updated keys during every time period. Therefore, during decryption, two-level key verification is done. At the first decryption stage, the key corresponding to that particular time period is required, then the original key is generated from that key and then employed for decrypting the original data. The proposed method is simulated using MATLAB tool and a detailed comparative results analysis is carried out. The performance of the proposed work is validated with the aid of performance metrics like Peak Signal to Noise Ratio (PSNR), number of changing pixel rate (NPCR) and unified averaged changed intensity (UACI). The experimental results stated that the presented model has resulted to a higher PSNR of 62.29 dB, NPCR of 99.23%, and UACI of 23.67%.

An efficient DNA-inspired image encryption algorithm based on hyper-chaotic maps and wavelet fusion

This paper introduces an efficient image encryption method which is inspired by Deoxyribo Nucleic Acid (DNA) nitrogenous bases. Amongst its advantages is that it is highly sensitive to many types of attacks. A confused version of an image (using a simple chaotic map) is DNA coded using its four types of nitrogenous bases. The resultant image made of DNA sequences is transformed into four sub-images A, C, G, and T, DNA’s bases. Chen’s hyper-chaotic map is used to diffuse the resultant images, according to a control code. The four DNA images are then combined using a wavelet confusion algorithm to produce an encrypted image. Numerical simulation was used to examine the effectiveness of the encrypted image against different attacks. The results were compared to those of other encryption algorithms and proved that the proposed encryption method delivers better results than other conventional ones including DNA based with different chaotic maps and double random phase encoding.

A Novel Chaotic Image Encryption Algorithm Based on Latin Square and Random Shift.

To realize the safe transmission of images, a chaotic image encryption algorithm based on Latin square and random shift is proposed. The algorithm consists of four parts: key generation, pixel scrambling, pixel replacement, and bit scrambling. Firstly, the key is generated from the plain image to improve the sensitivity of the encryption method. Secondly, each pixel in each row of the image matrix is moved cyclically to the right, in turn, to change the position of the image pixel and realize pixel position scrambling. Then, a 256-order Latin square matrix composed of a chaotic sequence is used as a lookup table, and the replacement coordinates are calculated based on the image pixel value and the chaotic sequence value, replacing the corresponding coordinate elements in the image matrix. Finally, decompose the bitplane of the image matrix and combine it into two-bit matrices, scramble the two bit matrices, respectively, with the Latin square matrix, recombine the scrambled two-bit matrices, and convert them into decimal to obtain the ciphertext image. In the proposed encryption method, all the Latin square matrices used are generated by chaotic sequences, further enhancing the complexity of the generated Latin square matrix and improving the algorithm's security. Experimental results and security analysis show that the proposed algorithm has good security performance and is suitable for image encryption.

Color image encryption using linear feedback shift registers by three dimensional permutation and substitution operations

This study proposes a scale-invariant digital color image encryption method that includes three main steps the pre-substitution, the 3D scale-invariant modular chaotic map, and the post-substitution. 1) The pre-substitution: At the first stage, pixels of plain sub-images are XOR with different key patterns. By starting from one of the plain sub-images, the pixels of the selected plain sub-image is XOR with the initial key, and the result is used as the cipher sub-image and as the next key pattern for performing XOR operations on the next plain sub-image. In other words, the XOR result of each step is used as the next step key pattern, 2) the 3D permutation: At the second stage, first the red, green, and blue components of a $M times N$ color image is divided to m sub-images with size $n times n$. Then m sub-images are partitioned into $k = leftlceil {frac{m}{n}} rightrceil $ windows $W_1$ to $W_k$ with size $n times n$ sub-images. The last two i؟¼$W_k-1$ and i؟¼$W_k$ windows may be overlap in several sub-images. Finally, the three-dimensional modular chaotic maps are performed on the $W_1$i؟¼ to $W_k$i؟¼ windows with MIPF keys and selected by LFSR, 3) the post-substitution: At the final stage, the $M times N$ color image is initially divided into a set of color sub-images. Then, the 24-bit pixels of each sub-images are circularly shifted with several bits specified in the secret key. Modular arithmetic is used in the 3D scale-invariant chaotic maps to increase keyspace and enhance security parameters. With repeat at least one round of main steps, the proposed encryption scheme reaches optimum parameter values and it is highly sensitive to minor differences in both secret key and plain image. The proposed encryption method for images improves the standard parameters of evaluation such as entropy, adjacent pixel correlations, histogram, and expanded keyspace.

New DNA Coded Fuzzy Based (DNAFZ) S-Boxes: Application to Robust Image Encryption Using Hyper Chaotic Maps

This article proposes a novel approach of improvising the cryptographic features of substitution-boxes (S-Box) based on the Choquet Fuzzy Integral (CFI) and DNA techniques. First, we propose a strong structure for the construction of four S-Boxes using CFI. The key for generating the CFI based (FZ) S-Boxes consists of two parts, namely, an external secret key and a secret image. Each of these FZ S-boxes is then encoded using DNA techniques, with dynamic rules selection which is dictated by a secret control code. The resultant four S-boxes are designated as DNAFZ S-Boxes. To apply for image encryption, the plain image is, at first 8-bit binary-coded, shuffled by an M-sequence, and down-sampled into four sub-images. Subsequently, the pixel values of each sub-image are replaced with the corresponding values of one of the four DNAFZ S-Boxes. Next, each DNAFZ encoded sub-image is diffused with a different DNA encoded chaotic sequence from Chen’s hyper-chaotic map. Finally, the four DNAFZ/Chaotic encoded sub-images are combined to build the final encrypted image. The proposed DNAFZ S-boxes shows excellent statistical properties under majority logic criterions such as correlation, homogeneity, energy, entropy, and contrast. Moreover, numerical simulation is used to examine the efficacy of encrypted images against different attacks. In particular, the values of the pixel correlation coefficient are found to be quite small either horizontally, vertically, or diagonally (between 7.8597e-04 and 0.00527, between 8.7856e-04 and 0.00452, and between 0.00241 and 0.00021, respectively). In addition, the information entropy of the encrypted image is found to be within the range of (7.9965:7.9989) which is very near to the ideal value of 8. As for the UACI and the NPCR, they are in the ranges between 33.46 and 33.32 and between 99.58 and 99.62, respectively. These values are also very close to the optimum ones. The results are compared to those of other encryption algorithms and proved that the proposed encryption method delivers better results than other conventional ones including LSS chaotic map, Arnold transforms, Dynamic Henon map, Hybrid chaotic map optimized substitution, and cubic S-Box.

Security of Digital Images Based on 3D Arnold Cat Map and Elliptic Curve

Security of digital data is an important task in the present era. In this paper, we propose a new scheme of digital image encryption and decryption method based on three-dimensional (3D) Arnold cat map (ACM) and elliptic curve. In this proposed encryption method, we have applied 3D ACM on the digital color image which performs the dual encryption first, it performs the permutation and second, it performs the substitution of image pixels. After that, elliptic curve cryptography (ECC) is used to encrypt the image, for this a mapping method is proposed to convert the pixels of the image as points on the elliptic curve. Further, a mapping inverting method is proposed for decryption and then 3D inverse Arnold cat map (iACM) is applied to get the original image. The statistical and security analyses are done on various images and the experimental results show the robustness of the proposed method.

A Novel Approach to Data Encryption Based on Matrix Computations

In this paper, we provide a new approach to data encryption using generalized inverses. Encryption is based on the implementation of weighted Moore–Penrose inverse A†MN(nxm) over the nx8 constant matrix. The square Hermitian positive definite matrix N8x8 p is the key. The proposed solution represents a very strong key since the number of different variants of positive definite matrices of order 8 is huge. We have provided NIST (National Institute of Standards and Technology) quality assurance tests for a random generated Hermitian matrix (a total of 10 different tests and additional analysis with approximate entropy and random digression). In the additional testing of the quality of the random matrix generated, we can conclude that the results of our analysis satisfy the defined strict requirements. This proposed MP encryption method can be applied effectively in the encryption and decryption of images in multi-party communications. In the experimental part of this paper, we give a comparison of encryption methods between machine learning methods. Machine learning algorithms could be compared by achieved results of classification concentrating on classes. In a comparative analysis, we give results of classifying of advanced encryption standard (AES) algorithm and proposed encryption method based on Moore–Penrose inverse.

Image Encryption Based on Matrix Factorization

In this paper, we present a matrix decomposition-based approach for image cryptography. The proposed method consists of decomposing the image into different component and scrambling the components to form the image encryption technique. We use two different type of matrix decomposition techniques to check the efficiency of proposed encryption method. The decomposition techniques used are Independent component analysis (ICA) and Non-Negative Matrix factorization (NMF). The proposed technique has unique user defined parameters (key) such as decomposition method, number of decomposition components and order in which the components are arranged. The unique encryption technique is designed on the basis of these key parameters. The original image can be reconstructed at the decryption end only if the selected parameters are known to the user. The design examples for both decomposition approaches are presented for illustration purpose. We analyze the complexity and encryption time of cryptography system. Results prove that the proposed scheme is more secure as it has less correlation between the input image and the encrypted version of the same as compared to state-of-art methods. The computation time of the proposed approach is found to be comparable.

Cryptosystems using an improving hiding technique based on latin square and magic square

<p>Hackers should be prevented from disclosing sensitive data when sent from one device to another over the network. Therefore, the proposed method was established to prevent the attackers from exploiting the vulnerabilities of the redundancy in the ciphertext and enhances the substitution and permutation operations of the encryption process .the solution was performed by eliminates these duplicates by hiding the ciphertext into a submatrix 4 x4 that chooses randomly from magic square 16x16 in each ciphering process. Two techniques of encrypted and hiding were executed in the encryption stage by using a magic square size 3 × 3 and Latin square size 3 × 3 to providing more permutation and also to ensure an inverse matrix of decryption operation be available. In the hiding stage, the ciphertext was hidden into a 16×16 matrix that includes 16 sub-magic squares to eliminate the duplicates in the ciphertext. Where all elements that uses were polynomial numbers of a finite field of degree Galois Fields GF ( ). The proposed technique is robust against disclosing the repetition encrypted data based on the result of Avalanche Effect in an accepted ratio (62%) and the results of the output of the proposed encryption method have acceptable randomness based on the results of the p-values (0.629515) of the National Institute of Standards and Technology (NIST) randomness tests. The work can be considered significant in the field of encrypting databases because the repetition of encrypted data inside databases is considered an important vulnerability that helps to guess the plaintext from the encrypted text.</p>

Data Encryption for Internet of Things Applications Based on Catalan Objects and Two Combinatorial Structures

This article presents a novel data encryption technique suitable for Internet of Things (IoT) applications. The cryptosystem is based on the application of a Catalan object (as a cryptographic key) that provides encryption based on combinatorial structures with noncrossing or nonnested matching. The experimental part of this article includes a comparative analysis of the proposed encryption method with the Catalan numbers and data encryption standard (DES) algorithm, which is performed with machine learning-based identification of the encryption method using ciphertext only. These tests showed that it is much more difficult to recognize ciphertext generated with the Catalan method than one made with the DES algorithm. System reliability depends on the quality of the key, therefore, statistical testing proposed by National Institute of Standards and Technology was also performed. Twelve standard tests, the approximate entropy measurement, and random digression complexity analysis are applied in order to evaluate the quality of the generated Catalan key. A proposal for applying this method in e-Health IoT is also given. Possibilities of applying this method in the IoT applications for smart cities data storage and processing are provided.

A Novel Hybrid Secure Method Based on DNA Encoding Encryption and Spiral Scrambling in Chaotic OFDM-PON

This paper proposes a novel hybrid secure method based on improved deoxyribonucleic acid (DNA) encoding encryption and spiral scrambling in chaotic OFDM-PON for enhancing the physical-layer security. In the improved DNA encoding encryption, the odd-even cross-bit DNA encoding, base scrambling and base-level substitution are determined by chaotic sequences. For each binary and base, the selected encoding rules and base scrambling methods are dynamically changing, which enhances the robustness against malicious attacks by attackers. In the spiral scrambling process, the QAM symbol matrix is divided into several blocks, and these blocks are scrambled. In the scrambling of the plural matrix, the position where the spiral starts and the orientation and direction of the traversal are also controlled by the chaotic sequences. By employing DNA encoding encryption and spiral scrambling, a key space of $\sim \!{10^{135}}$ can be achieved in the multi-fold encryption of the proposed scheme, which can improve the physical-layer security. The encrypted 16-QAM OFDM data are successfully transmitted over a 60-km SSMF in OFDM-PON. The simulation results demonstrate that it has better BER performance at the BER of ${10^{ - 3}}$ than other schemes. The proposed encryption method can effectively protect data from attacks by eavesdroppers or illegal users.

Triple layer image security using bit-shift, chaos, and stream encryption

One popular image security technique is image encryption. This research proposes an image encryption technique that consists of three encryption layers, i.e. bit-shift encryption, chaos-based encryption, and stream encryption. The chaos algorithm used is Arnold's chaotic map, while the stream cipher algorithm used is RC4. Each layer has different cryptology characteristics in order to obtain safer image encryption. The characteristics of cryptology are permutation, confusion, diffusion, and substitution. The combination of the proposed encryption method aims to secure images against various attacks, especially attacks on statistics and differentials. The encryption method testing is done by various measuring instruments such as statistical analysis, i.e. entropy information, avalanche effect, and histogram, differential analysis, i.e. UACI and NPCR, visual analysis using PSNR and SSIM, and bit error ratio. Based on the results of experiments that the encryption method that we propose can work excellently based on various measurement instruments. The decryption process can also work perfectly this is evidenced by the ∞ value based on PSNR, and zero value based on SSIM and BER.

Analysis of zig-zag scan based modified feedback convolution algorithm against differential attacks and its application to image encryption

In this paper, a novel zig-zag scan-based feedback convolution algorithm for image encryption against differential attacks is proposed. The two measures Number of Pixel Change Rate (NPCR) and Unified Average Changed Intensity (UACI) are commonly utilized for analyzing the differential attacks. From the study of the existing papers, even though high Number of Pixel Change Rate and Unified Average Changed Intensity values are obtained, a few values lie in the critical range of α-level significance which in turn increase the possibility of differential attacks. To overcome differential attacks, two aspects of scanning with different test cases are analyzed and from these analyses, it is concluded that zig-zag scan based feedback convolution in forward and reverse direction achieves good Number of Pixel Change Rate and Unified Average Changed Intensity without critical values. Zig-zag scan based feedback convolution in forward and reverse direction is enforced for key sequence generation and applied in diffusion process to achieve high level of security. Moreover, plain image related initial seed is also generated to overcome the chosen/known plain text attacks. Both numerical and theoretical analyses are performed to prove that the proposed encryption method is resistant to differential attacks. General security measures are carried out for the proposed method to validate its security level. From the simulations, it is shown that the proposed methodology has good keyspace, high key sensitivity, good randomness, and uniform distribution of cipher image pixels.

Multi scrolls chaotic encryption for physical layer security in OFDM-PON

We propose a novel 3-dimension (3-D) multi scrolls chaotic encryption for physical layer security in OFDM-PON. Compared with the hyper Chen scheme, the proposed encryption method has lower encryption complexity and larger key space due to the 3-D multi scrolls characteristic of self-contained limiting amplitude and extreme initial value sensitivity. We verify the proposed multi scrolls encryption algorithm in 25-Gb/s DD-OFDM-PON system. The experimental results show that normal decryption is possible only if the key is fully acquired without any tiny error. The key space of the proposed scheme is up to 10332. We also transmit classical images ‘Lena’ in the experimental system to verify the practicability of the proposed encryption algorithm. The experimental result show that our method is promising for physical layer security of OFDM-PON.

A novel method for lossless image compression and encryption based on LWT, SPIHT and cellular automata

In this paper, a novel method for lossless image encryption based on set partitioning in hierarchical trees and cellular automata. The proposed encryption method embeds the encryption into the compression process, in which a small part of the data is encrypted quickly, while maintaining the good coding characteristics of set partitioning in hierarchical trees (SPIHT). The proposed encryption system adopts three stages of scrambling and diffusion. In each stage of encryption, different chaotic systems are used to generate the plaintext-related key stream to maintain high security and to resist some attacks. Moreover, the channel length of the coded-and-compressed color image is more uncertain, resulting into higher difficulty for attackers to decipher the algorithm. The experimental results indicate that the length of bitstream is compressed to 50% of the original image, showing that our proposed algorithm has higher lossless compression ratio compared with the existing algorithms. Meanwhile, the encryption scheme passes the entropy analysis, sensitivity analysis, lossless recovery test, and SP800-22 test.

Novel secure surgical telepresence using enhanced advanced encryption standard: during, pre and post surgery

Security during surgical telepresence has not yet been sufficiently considered. This paper aims to propose a solution to enhance security during surgery between the site of surgery (local site) and the site that hosts the expert surgeon (remote site). The proposed system consists of an Enhanced Advanced Encryption Standard, which enhances the confusion and diffusion of the encrypted video. Two-factor authentication have been used biometrics and a one-time password complemented by archiving that are also considered for pre and post-surgery respectively. In the proposed system the substitution box and shift rows are eliminated and replaced with mix row step, this leads to increase the complexity of the proposed system. Also the Henon chaiotic map was used in the key generation process, and this is provided more randomness. The results demonstrate that the proposed encryption method increases the entropy of the encrypted video by 0.25% compared to the Advanced Encryption Standard algorithm. In addition, a reduction in processing time have been achieved, for encryption and decryption by 24% and 38% respectively. For testing the strength of security, we measure the plain-text sensitivity by using the information entropy, Peak Signal-to-Noise Ratio (PSNR) and Mean Square Error (MSE). Also, the encryption/decryption time is measured for the proposed algorithm and state of the art algorithm. The decreasing in PSNR means the stronger encryption algorithm, and while the PSNR of the proposed system was decreased then this leads to better encryption method. The proposed system aims to enhance surgical network security to make it viable for implementation during surgery where data is exchanged under conditions of telepresence. The proposed system eliminates the limitation of the traditional AES algorithm. The proposed EAES provides high security by increasing the entropy while decreasing the encryption and decryption time.

Scale invariant digital image encryption using 3D modular chaotic map

Cryptography techniques are used to preserve the privacy and integrity of image media. Most proposed cryptographic images methods based on chaotic maps are dependent upon image sizes and most of them worked on square images. Tackling this problem, a scale invariant gray level image encryption method is proposed by means of 3D modular chaotic map. Initially, a 2D image with desirable size M × N is converted into a 3D image with m sub-images by size n × n. Optimizing the calculation, the parameters m and n should be appropriately selected. Having diffusion and confusion properties, two steps of 3D substitution and a 3D permutation step are used. In the 3D substitution steps, the pixels value of sub-images will be changed using the XOR operators and the circular shift. In the permutation step the pixels position of sub-images will be changed using 3D modular chaotic map, In this case, the m sub-images are divided into $$ k=\left\lceil \frac{m}{n}\right\rceil $$ equal size windows which each window has n sub-images with size n × n, and the 3D modular chaotic map is performed on any window with independent parameters. Depending upon the value of m, the number of windows is greater than or equal to 1; for k > 1, the last two windows may overlap to perform 3D chaotic map operation. Accelerating the proposed encryption method, the 3D chaotic map operations on windows can be implemented in parallel. The proposed method, in comparison with other methods of image encryption, improves the statistical parameters of cryptographic analysis, key space, and speed.

Secure image encryption scheme using high efficiency word-oriented feedback shift register over finite field

Image encryption is an evolving technique in the arena of data communication. In the last decade, many encryption schemes have been suggested. Unfortunately, most of the current schemes are unable to maintain a balance between security and computational complexity. To overcome this challenge, this paper introduces a novel encryption scheme that effectively maintains the trade-off between security and computational complexity. Initially, the plain image is randomized and scrambled by the Logistic map and Arnold’s scrambling technique. The intermediate image found above, is then encrypted by the special word-oriented feedback shift register (wfsr) to get the final cipher image. Wfsr is inherently suitable for high-quality pseudorandom number generation with good statistical properties. It usually posses high throughput. Further, the elliptic curve Diffie-Hellman (ECDH) is used for sharing the keys required for encryption and decryption process. The performance of the proposed cryptosystem is evaluated based on several statistical properties of the cipher image, the resistance of the cipher image to various attacks, and time required for encryption and key sharing process. The statistical properties of the encrypted image are found out through histogram analysis, correlation and entropy finding, key sensitivity analysis, chi-square test, and NIST randomness test. The resistance of the encrypted image to various attacks is either found out experimentally or indirectly by using metrics like Unified Average Changing Intensity (UACI), Number of Pixel Changing Rate (NPCR). The proposed encryption method compares favorably with similar image encryption schemes.

An asymmetric and optimized encryption method to protect the confidentiality of 3D mesh model

3D models are widely used in computer graphics, design and manufacture engineering, art animation and entertainment. With the universal of acquisition equipment and sensors, a huge number of 3D models are generated, which are becoming the major source of engineering data. How to preserve the privacy of the 3D models is a challenge issue. In this paper, an asymmetric and optimized encryption method is presented to protect the 3D mesh models. Firstly, we propose an asymmetric encryption method for 3D mesh models to overcome the drawbacks of traditional symmetric encryption. The primary benefit is that our approach can enhance the security of the key. Secondly, we extend the typically asymmetric encryption algorithm from integer domain to float domain. In our method, we present a normalization function to map the float DC (Discrete Cosine) coefficients to integer domain. Thirdly, considering that the shape error and encryption/decryption computation cost are contradictory in the normalization mapping, we formulate the contradiction as a multi-objective optimization problem. And then, we propose a multi-objective solution to find an optimized mapping range for encryption/decryption efficiently. Furthermore, benefiting from the proposed asymmetric encryption framework, we continue to put forward a method to check the integrity of the encrypted 3D mesh model, in which the digest is encrypted twice to generate digital signature more safely. The proposed method has been tested on 3D mesh models from Stanford university and other sources to demonstrate the effect of the proposed encryption method and optimization mechanism.

Designing digital image encryption using 2D and 3D reversible modular chaotic maps

This paper presents a gray level image encryption method based on permutation operation and diffusion operation on image pixels. In diffusion operation, the image is subdivided into equal size sub-images, and the pixels of each sub-image are changed with the help of logical operators and circular shifts. In the permutation operation, the image is first divided into four bit-plate images, and the pixels of each bit-plate image are permuted in parallel by chaotic maps. In this research, reversible two-dimensional and three-dimensional chaotic maps based on modular mathematics are proposed to increase the key space, improve speed and period. The key space exponentially is increased as compared to standard chaotic maps through defining the reversibility in residue matrices, chaotic map in 3D space and changing the key in each round. In the proposed modular 3D chaotic map, the 2D image is first converted into 3D space, and then mapping operations are carried out for permuting the pixels into 3D space. The proposed encryption method for images improves the standard parameters of evaluation such as entropy, adjacent pixel correlations, histogram, and expanded key space.