Cyclic Shift Research Articles

An Identical Code–Data Based Nonorthogonal Multiple Access

ABSTRACTNonorthogonal multiple access (NOMA) is a promising technique operating with limited resources. NOMA can be executed in both power and code domains. Cyclic interleaved NOMA strategies are debated in recent literature, combining power and code domains. Identical code cyclic shift (ICCS) transmission is viewed to be a bridge between code division access and NOMA. We propose identical code–data cyclic shift NOMA (ICDCS‐NOMA) in which the code and data are cyclically shifted in distinction to simple cyclic interleaved transmission introduced in our earlier work and the ICCS transmission. The cell‐edge user in a NOMA pair engages its signal transmission using ICDCS; in contrast, the cell‐center user prefers simple cyclic interleaved transmission. The spread data stream and its cyclic shifted version are blended in ICDCS, followed by cyclic interleaving. A distinct and extreme fading channel pair is assumed with the same number of paths for the edge and center users. Diversity combining multipath signals is embraced at the edge user terminal, and frequency domain equalization (FDE)/matched filter (MF) receiver is employed at the center user. The simulation indicates the dominance of the proposed ICDCS‐NOMA transmission in terms of the attained diversity gain over the conventional, ICCS, and simple cyclic interleaved transmissions.

Cyclic shift short-distance attention for defect detection of fine etching mesh

Abstract Based on the deficiency of the existing Swin Transformer in the detection of surface defects in metal etched grids, i.e. the isolation of information transmission between different windows, and the limitations of image matrix size and network structure,which make it not suitable for long sequence data processing and dense prediction scenarios, a defect detection method for metal etching nets based on Cyclic shift Long Short Distance Attention (C-LSDA) is proposed. In the proposed method, cross-scale features are used to capture long and short distance relationships,and enhance the feature transfer between windows. Tracking position bias (TPB) is also used to improve relative position bias (RPB), in order to help the model to better understand the spatial relationships in the input data. In addition, the image is downsampled at various scales, so that the proposed method can be suitable for long sequence data processing and dense prediction scenarios. In order to improve the detection accuracy of small targets. a multi-feature fusion pyramid network (MFFPN) for feature fusion is also proposed. The experimental results show that the proposed method is significantly superior to the traditional CNN recognition method and the transformer recognition method. The proposed methodhas good identification accuracy and low computational cost.

Adaptive content-aware spatial regularized correlation filter tracking algorithm

In order to solve the annoying boundary effects in correlation filter (CF) trackers induced by cyclic shift when sampling training patches, and improve the tracking performance, an adaptive content aware spatially regularized correlation filter (ACSRCF) is proposed. Firstly, real negative samples are generated from the background area around the target object, so as to alleviate the filter degradation by the fake negative samples induced from the circularly shifted object patches. Secondly, the locality sensitive histogram (LSH) based foreground feature is extracted and incorporated with the spatial regularization weight which is updated adaptively according to the varied object-oriented appearances. Thereafter, the CF model is optimized using the alternative direction method of multipliers (ADMM) in which the model is decomposed into two sub-problems and the LSH-based features are used in iteration for obtaining the optimal solutions. Finally, the proposed method is evaluated on 5 public benchmarks. The experimental results show that the accuracy and success rate scores of our method on OTB 50 dataset are 90.3%and 66.1%, respectively, exceeding the other CF trackers .The data on the OTB100 dataset is 92.2%and 69.2%, and the accuracy first ranks among all the trackers, while the success rate is ahead of other CF trackers.

On Broadcast Schemes of Knödel Graphs

Knödel graphs on even number of vertices serve as crucial components in constructing various broadcast graphs, particularly those on an odd number of vertices. The efficacy of these constructions heavily relies on the chosen broadcast scheme. Dimensional broadcast schemes are widely employed for broadcasting Knödel graphs. This paper delves into the investigation of standard and reverse dimensional broadcast schemes identifying numerous valid schemes. Specifically, let [Formula: see text] be a Knödel graph of order [Formula: see text] and [Formula: see text]. We explore the impact of [Formula: see text] cyclic shifts on both standard and reverse dimensional broadcast schemes of Knödel graphs, where [Formula: see text], with repetition of the second dimension.

Synchronization of M-sequences based on fast Нadamard transform

Options have been developed for constructing circulant matrices of any M-sequence (MS) based on automorphic multiplicative groups of the extended Galois field, constructed using an irreducible primitive polynomial, on the basis of which the original MS is formed. The result of this approach is the identification of new methods for transforming MS circulant matrices to a matrix of Walsh functions, ordered by the powers of the antiderivative element of the field. It is shown for the first time that, depending on the initial conditions of the transformation, a set of any number of any cyclic shifts of the MP, shifted relative to each other by one symbol, can be transformed to any rows of the ordered matrix of Walsh functions, following one another. This circumstance makes it possible to simplify the MS synchronization algorithm for a known range of its cyclic shifts, especially in the case of large periods of its repetition, and also to reduce the computational complexity of the processing algorithm when working in a truncated basis of Walsh–Hadamard functions.

A Low-Cost, Portable, Multi-Cancer Screening Device Based on a Ratio Fluorometry and Signal Correlation Technique.

The autofluorescence of erythrocyte porphyrins has emerged as a potential method for multi-cancer early detection (MCED). With this method's dependence on research-grade spectrofluorometers, significant improvements in instrumentation are necessary to translate its potential into clinical practice, as with any promising medical technology. To fill this gap, in this paper, we present an automated ratio porphyrin analyzer for cancer screening (ARPA-CS), a low-cost, portable, and automated instrument for MCED via the ratio fluorometry of porphyrins. The ARPA-CS aims to facilitate cancer screening in an inexpensive, rapid, non-invasive, and reasonably accurate manner for use in primary clinics or at point of care. To accomplish this, the ARPA-CS uses an ultraviolet-excited optical apparatus for ratio fluorometry that features two photodetectors for detection at 590 and 630 nm. Additionally, it incorporates a synchronous detector for the precision measurement of signals based on the Walsh-ordered Walsh-Hadamard transform (WHT)w and circular shift. To estimate its single-photodetector capability, we established a linear calibration curve for the ARBA-CS exceeding four orders of magnitude with a linearity of up to 0.992 and a low detection limit of 0.296 µg/mL for riboflavin. The ARPA-CS also exhibited excellent repeatability (0.21%) and stability (0.60%). Moreover, the ratio fluorometry of three serially diluted standard solutions of riboflavin yielded a ratio of 0.4, which agrees with that expected based on the known emission spectra of riboflavin. Additionally, the ratio fluorometry of the porphyrin solution yielded a ratio of 49.82, which was ascribed to the predominant concentration of protoporphyrin IX in the brown eggshells, as confirmed in several studies. This study validates this instrument for the ratio fluorometry of porphyrins as a biomarker for MCED. Nevertheless, large and well-designed clinical trials are necessary to further elaborate more on this matter.

Synchronization of Gold sequences based on fast transform in a truncated basis of Walsh–Hadamard functions

Based on the analysis of the structures of isomorphic multiplicative groups of extended Galois fields, it is established that any cyclic shift of a pseudo-random Gold sequence can be transformed into a function belonging to the complete set of analogues of Rademacher functions of the corresponding dimension. This made it possible to develop a new algorithm for fast synchronization of Gold sequences based on the calculation of their discrete convolution using fast spectral transformation in a truncated basis of Walsh–Hadamard functions. The gain of the developed algorithm in terms of the number of arithmetic operations compared to the traditional method of calculating discrete convolution increases with increasing sequence length N and for N=511.1023 is approximately 3.4 times.

Analysis and evaluation of multi-state wear mechanism of elastic-flexible thin-walled bearings

EFTWBs (Elastic-flexible thin-walled bearings) are mainly used in harmonic reducers. Under the condition of large reduction ratio and cyclic rotation, LFW (linear fretting wear), CFW (curve fretting wear) and CRF (complete rolling friction) appear in the bearing raceway. In this study, LFW and CFW experiments were carried out, and the relationship between coefficient of friction and surface hardness was analyzed. Meanwhile, the multi-dimensional analysis (surface hardness, residual stress, surface/subsurface retained austenite) of the raceway surface integrity of EFTWBs after 8000 h of high service was analyzed. Combined with the manufacturing process of EFTWBs and the above conclusions, the multi-state wear mechanism of raceway was comprehensively evaluated. The evaluation conclusions show that the raceway of EFTWBs contained CRF (including pitting and spalling) and sliding fretting wear (including LFW and CFW). The axial and tangential residual stresses of the untested and tested outer and inner ring raceways were compressive stresses. Grain delamination appeared on the tested outer and inner ring raceway subsurface (20 µm from the surface). The wear of the outer ring raceway of EFTWBs was greater than that of the inner ring, and the wear was multiple. A 430 nm nanocrystalline layer was found under FIB-TEM on the surface layer of the outer ring raceway, and the fracture and obvious dislocation appeared. The rolling-sliding wear mechanism of EFTWBs raceway was comprehensively evaluated. The accuracy of this analysis was verified by combining thin-walled ring and Hertz theories. There are many detailed conclusions which provide theoretical support and data analysis for relevant manufacturers of harmonic reducer and robot EFTWBs.

Blockchain-Assisted Keyword Search Scheme for SWIM Service Based on Improved CSC-Cuckoo Filter

With the rapid development of the civil aviation industry, the demand for secure sharing of civil aviation data is increasing. As a global platform for secure sharing of civil aviation data, the security of the System Wide Information Management (SWIM) system is of great concern. SWIM adopts a service-oriented architecture and realizes the interaction of civil aviation data through a publish-subscribe model. To protect the service privacy while enabling subscribers to subscribe to the service quickly and securely, this paper proposes an efficient Circular Shift and Coalesce-Cuckoo Filter (CSC-CF)-based service Keyword Search (CCKS) scheme assisted by blockchain. This scheme uses the Symmetric-key Hidden Vector Encryption (SHVE) algorithm to encrypt and match service indexes and trapdoors to protect service privacy; the CSC-CF structure is applied to keyword search, which can effectively improve the efficiency of SWIM user subscription service. To improve search accuracy and space utilization, we propose the improved CCKS (ICCKS) scheme by optimizing the query algorithm of CSC-CF and setting a threshold for the number of keyword query failures. ICCKS improves search accuracy by 5–20% compared to CCKS when the filter’s space utilization is between 60 and 90%. Additionally, the scheme stores service topic indexes and registry on the blockchain and implements a smart contract to match indexes and subscription trapdoors, ensuring the integrity and trustworthiness of service topics and registry. Security analysis and experimental simulations demonstrate that the scheme is effective and secure in the SWIM system.

Transcriptional profiling elucidates biofilm functionality in the dynamic environment of an enhanced biological phosphorus removal reactor

ABSTRACT Recently, biofilms, complex and dynamic structures of microorganisms, have been applied to enhanced biological phosphorus removal (EBPR), a wastewater treatment configuration dependent on cyclic shifts between anaerobic and aerobic conditions. In this study, comparative metagenomics and metatranscriptomics were performed on biofilms collected from seven sites of a moving-bed-biofilm-reactor-based EBPR process. The aim was to examine the functional ecology of phosphorus-accumulating biofilms throughout a single EBPR cycle. Taxonomic profiling revealed high microbial diversity, stable throughout the EBPR cycle. The dominant phosphorus-accumulating organisms (PAOs) were identified as Candidatus accumulibacter, Candidatus phosphoribacter, and Candidatus lutibacillus. However, these did not show the highest transcriptional activities. Propionivibrio, a potential glycogen-accumulating organism, was the most transcriptionally active. Comparative analysis of biofilms from different EBPR stages showed a progressive change in metatranscriptome composition, correlating with nutrient removal. Analysis of differentially expressed genes in abundant PAOs revealed key genes associated with the uptake of phosphorus, degradation of glycogen, biosynthesis of polyhydroxyalkanoates, and acetate production. In conclusion, this study reveals that biofilms possess the capability to adapt to environmental fluctuations primarily through alterations in microbial gene expression activity and subsequent metabolic modulation, and dominant taxa may not necessarily exhibit the highest transcriptional activity in complex microbial communities.

Perceived Trajectories of Cyclic Sound Movement

Binaural beats are a phenomenon that occurs during dichotic stimulation due to binaural integration. It takes the form of cyclic movement of the sound image in the listener’s acoustic space when the beat frequency range is below 3 Hz. Our subjects used the inserted earphones to listen to the stimuli that created a sense of sound movement due to changes in the interaural time difference (ITD). We used three types of dichotic stimuli which simulated smooth azimuthal cyclic movement and cyclic abrupt shifts. The ITD changes determined central or lateral positions of movement trajectories. The results confirm that both types of movement created the effect of binaural beats. The range of beats depended on the spatial position of the trajectory: in the frontal sector of acoustic space, the range of beats was greater than on the left or right. The perceived trajectories of smooth motion were shorter than the trajectories of abrupt shift. The influence of spatial position on the perceived trajectory length is interpreted from the standpoint of nonlinear features of lateralization. It is suggested that the effect of ITD pattern on the perceived trajectory length is mediated by temporal integration mechanisms of binaural hearing.

Oxidation micromechanics and contribution during the low-cycle fatigue failure of a Ni-based single crystal superalloy

Understanding the comprehensive factors of oxidation behaviors and revealing their contribution to fatigue failure is of great importance. The low-cycle fatigue (LCF) coupled oxidation behavior of a novel low-cost third generation Ni-based single crystal superalloy with only 3 wt% of Re at 800 ℃ and 1000 ℃ was studied in the present work. The results indicated that oxidation-induced crack initiation was specifically responsible for the drastic reduction in LCF life at high temperatures, as opposed to the unobvious creep deterioration and the inferior fatigue damage via crack propagation in slow model-I. However, it was found that the preferential spallation of the weakly bonded (Ni, Co)O layer was beneficial in suppressing crack initiation. In terms of crack propagation, the proceeding oxidation of nearby fatigue cracks could boost dislocation recovery process, which thereby improved the toughness of the surrounding substrate to decelerate crack propagation. Noteworthy, a specific asymmetric oxidation phenomenon in single crystal alloy was identified for its required cyclic crystal rotation in one single grain. Importantly, guidance for chemical composition optimization was proposed that future efforts should be made to reduce oxidation damage during fatigue deformation by lowering oxidation kinetics and increasing the bonding strength of oxide layers.

Circular phase shift migration based photoacoustic computational tomography

Abstract In the recent several decades, photoacoustic technique has proved to be capable of noninvasive biomedical imaging with scalable spatial resolution and high penetration depth. To achieve faithful image reconstruction, various method has been proposed, such as back projection, phase shift migration, model-based method, etc. These methods have simple implementations in homogeneous media, whereas in the cases of heterogeneous media (e.g., layered media), complicated modifications with respect to wave propagation at layer interface are always necessary. Here, we propose a frequency domain algorithm extension of phase shift migration in polar coordinates, which is obtained by making second order approximation to the optoacoustic point spread function in cylindrical coordinates and thereafter step by step wavenumber-frequency domain wave field extrapolation along the axial direction. Theoretical simulation and phantom experimental results demonstrate that the proposed circular phase shift migration method can well solve the layered heterogeneous reconstructive problem without modifying the wave propagation model. The acoustic diffraction limited acoustic resolution (up to 225 μm) and high imaging SNR (at least 16 dB) are obtained.

Automatic Intrusion Detection Model with Secure Data Storage on Cloud Using Adaptive Cyclic Shift Transposition with Enhanced ANFIS Classifier

Cloud computing has emerged as a pivotal technology in the computer electronics industry, offering users significant computing power and ample storage space. Security threats pose significant challenges to the progression of cloud computing, hindering its growth in the industry. Detecting intrusions is crucial for protecting cloud environments from harmful attacks. However, due to the complexity and vast amount of network data, building effective intrusion detection systems (IDS) for cloud setups is difficult. Traditional IDS have struggled to effectively mitigate these risks. To overcome these problems, we propose a novel feature selection technique with deep learning classifier-based intrusion detection and avoidance in a cloud environment. The suggested model is divided into four phases: feature selection, pre-processing, classification, and encryption. The initial step involves gathering the data from the dataset and pre-processing it. The Adaptive Walrus Optimization Algorithm (AWO) is then used to choose select optimal features, aiming to mitigate computational complexity and reduce time consumption. These selected features are then fed into an enhanced Adaptive Neuro-Fuzzy Inference System (EANFIS) classifier for accurate classification of normal and intruded data. Following classification, normal data undergoes encryption using the Adaptive Cyclic Shift Transposition (ACST) Algorithm to bolster security.For experimental evaluation two datasets used namely, KDDCup-99 and NSL-KDD. The proposed method notably achieves impressive accuracy rates of 98.47% for the NSL KDD dataset and 98.97% for the KDD-CUP99 dataset.

The Quantum Cyclic Rotation Gate

A circular shift operator (or cyclic rotation gate) ROTk\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${{\\,\\mathrm{\ exttt {ROT}}\\,}}_k$$\\end{document} applies a rightward (or leftward) shift to an input register of n qubits o by as many positions as encoded by an additional input k∈N\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$k \\in \\mathbb N$$\\end{document}. Specifically, the qubit at position x is moved to position (x+k)modn\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$(x+k) \\mod n$$\\end{document}. While it is known that there exists a quantum rotation operator that can be implemented in O(log(n))\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${{\\,\\mathrm{\\mathcal {O}}\\,}}(\\log (n))$$\\end{document}-time, through the repeated parallel application of the elementary Swap\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${{\\,\\mathrm{\ exttt {Swap}}\\,}}$$\\end{document} operators, there is no systematic procedure that concretely constructs the quantum operator ROT\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${{\\,\\mathrm{\ exttt {ROT}}\\,}}$$\\end{document} for variable size n of the quantum register and a variable parameter k. We fill the gap, providing a systematic implementation of the cyclic rotation operator (denoted ROT\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${{\\,\\mathrm{\ exttt {ROT}}\\,}}$$\\end{document}) in a quantum circuit model of computation whose depth is O(log(n))\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${{\\,\\mathrm{\\mathcal {O}}\\,}}(\\log (n))$$\\end{document}. We show how the circular shift operator can be utilized in quantum approaches to text processing, focusing on the problem of getting all possible cyclic rotations of a string in O(log2(n))\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${{\\,\\mathrm{\\mathcal {O}}\\,}}(\\log ^2(n))$$\\end{document} depth.

Optimizing the mechanical and corrosion properties of an ultrafine-grained Al-Cu-Mg alloy through cyclic deformation: Clusters and lattice defects

To optimize its corrosion and mechanical properties, an Al-Cu-Mg alloy is cyclically processed by high-pressure torsion (HPT), involving a 1/2 turn clockwise and a 1/2 turn counter-clockwise per cycle. The dislocation density increases to 3.04×1014 m−2 on 1 cycle HPT and decreases gradually to 2.23×1014 m−2 for higher cyclic rotations (i.e. 5 cycle HPT). Due to the rapid elimination of the geometrically necessary dislocations, the refinement of grain size in cyclic HPT is more efficient than the monotonic HPT (i.e. it decreases from 2.48 μm to 112 nm on 1 cycle HPT). The HPT samples are electrochemically corroded in a simulated seawater environment. 1-cycle HPT process causes a strong increase in hardness (to 232 HV) and an increase in corrosion potential (to −0.517 V). The trade-off between hardness/strength and corrosion resistance is broken on cyclic HPT processing. Aided by excess vacancies induced by HPT, Cu-Mg clusters form on and near grain boundaries through a ‘vacancy-pump’ mechanism, causing solute depleted zones (SDZ) adjacent to GBs. The combined effects of ultrafine grains, solute cluster segregation and SDZs enhance the strength and corrosion resistance of the Al-Cu-Mg alloys. This study provides a potential strategy to design the microstructures of an Al alloy, and to achieve a higher hardness and a better corrosion performance of that material.

General Structure and Properties of Cyclic Codes Over \(GF_2\)

This article provides a comprehensive analysis of cyclic codes in GF(2), focusing on their general structure and key properties. Cyclic codes are characterized by their generator polynomials, which define their structure and play a crucial role in encoding and decoding processes. The cyclical shift property, inherent in cyclic codes, facilitates efficient implementation using shift register circuits, making them practical for real-world applications. The discussion highlights the algebraic properties that distinguish cyclic codes from other linear block codes, emphasizing their ability to detect and correct errors.

Non-Abelian Hopf-Euler insulators

We discuss a class of three-band non-Abelian topological insulators in three dimensions that carry a single bulk Hopf index protected by spatiotemporal (PT) inversion symmetry. These phases may also host subdimensional topological invariants given by the Euler characteristic class, resulting in real Hopf-Euler insulators. Such systems naturally realize helical nodal structures in the three-dimensional Brillouin zone, providing a physical manifestation of the linking number described by the Hopf invariant. We show that, by opening a gap between the valence bands of these systems, one finds a fully-gapped “flag” phase, which displays a three-band multigap Pontryagin invariant. Unlike the previously reported PT-symmetric four-band real Hopf insulator, which hosts a Z⊕Z invariant, these phases are not unitarily equivalent to two copies of a complex two-band Hopf insulator. We show that such uncharted phases can be obtained through dimensional extension of two-dimensional Euler insulators, and that they support (i) an optical bulk integrated circular shift effect quantized by the Hopf invariant, (ii) quantum-geometric breathing in the real-space Wannier functions, and (iii) surface Euler topology on boundaries. Consequently, our findings pave the way for novel experimental realizations of real-space quantum geometry, as these systems may be directly simulated by utilizing synthetic dimensions in metamaterials or ultracold atoms. Published by the American Physical Society 2024

A novel plaintext-related image encryption and compression method based on a new coupled map lattices model

In this paper, we propose a new Sine-Logistic Map Coupled Map Lattices (SLMCML) model, which exhibits enhanced chaotic characteristics and more suitable for image encryption compared with the classical coupled map lattices. Based on the SLMCML system, we propose an image encryption and compression method. To improve the plaintext sensitivity of image cryptosystem, we propose a novel plaintext-related internal keys generation method, which can obviously improve the plaintext sensitivity of initial values of SLMCML system, thus improve the plaintext sensitivity of whole process of compression and encryption. Our proposed image encryption scheme contains several steps. Initially, the discrete wavelet transform (DWT) is utilized to convert original image into coefficient matrix. Then a plaintext relation method is constructed, which generate internal keys as initial values of SLMCML system. Next the coefficient matrix is permutated by permutation sequences generated by SLMCML system to cyclic shift for making the energy evenly distributed. Next the coefficient matrix is done sparse processing. The compressed sensing is employed to compress coefficient matrix. Subsequently, the compressive image is permutated with spiral traversal and twice zigzag transform. Finally, the permutated image is diffused with column diffusion to generate cipher image. Through some common security analyses, our proposed image encryption scheme has good security performance and excellent image recovery quality.

A visual security multi-key selection image encryption algorithm based on a new four-dimensional chaos and compressed sensing

In this article, a visual security image encryption algorithm based on compressed sensing is proposed. The algorithm consists of two stages: the compression and encryption stage and the embedding stage. The key streams in the compression and encryption stage are generated by a newly constructed four-dimensional discrete chaotic map, while the Gaussian measurement matrix is generated by a Chebyshev map, and both of their generations are related to the feature code of the carrier image, which enhances the security of the ciphertext. In the compression and encryption stage, a scrambling-cyclic shift-diffusion encryption structure is adopted for the compressed image in which the shift number in the cyclic shift stage and the diffusion key streams are dynamically changed according to each pixel value, so the algorithm can resist chosen plaintext attack. In the embedding stage, the carrier image is first subjected to integer wavelet transform to obtain the high-frequency and low-frequency components of the image, and then the intermediate ciphertext information is embedded into its high-frequency components. Finally, the carrier image is subjected to inverse integer wavelet transform to obtain a visually secure ciphertext image. The experimental results and security analysis indicate that the encryption scheme has a large key space, high decryption key sensitivity, similar histogram distribution between the carrier image and the visual security ciphertext image, and good robustness to noise attacks.