In the era of digitization and informatization, 3D models are used in a variety of fields, notably in medicine, engineering and design, seamlessly integrating into people's daily lives. Particularly within the medical field, 3D models enjoy extensive utilization. Consequently, this paper introduces a novel 3D medical model encryption algorithm, designated as 3D3A-SMA. First, a five-dimensional hyperchaotic system with multiple stability is applied to the encryption process of this algorithm. In this encryption algorithm, the vertex data of the 3D model is divided into integer and fractional parts and different diffusion methods are applied to them, respectively. A 3D Arnold spiral subregion diffusion based on chaotic system (3ASDC) is proposed to diffuse the integer part, and then, a selectable multiple spiral arrangement subregion diffusion (SMASD) is proposed to diffuse the fractional part. The simulation results and performance analysis show that the proposed encryption algorithm can accurately encrypt and decrypt the 3D medical model. The numerical results in the performance analysis are very close to the ideal values, with the information entropy of the ciphertext and each dimension reaching 7.998. In addition, the correlation within the ciphertext is also very close to the ideal value of 0.000, The algorithm also shows strong resistance to common attacks.

On the basis of single axis coupling for constructing conservative chaos, a method for constructing a biaxial multitype conservative chaotic system is proposed. The method constructs more types of chaotic systems with a wider range of traversal. When coupling the Eulerian subbody biaxially, it is discovered that the structural matrix is able to exhibit two different multistates, namely, 0 and the opposite state, 0 and the same state, and depending on the location of the introduced adjustable parameter, the constructed chaotic equations also exhibit multiple types. When the structure matrix exhibits 0 and opposite state, the chaotic equations exhibit three types, which are opposite, one-parameter, and two-parameter types; and when the structure matrix is 0 and the same state, the chaotic equations exhibit the same type, one-parameter, and two-parameter types. The relationship of each pair of adjustable parameters satisfies the structure matrix antisymmetry, which leads to many types of Hamiltonian conservative chaotic systems that can transition between quasi-periodic, hyperchaotic, and chaotic states, all of which pass the NIST test, increasing the diversity of chaotic system choices in image encryption. The chaotic system is applied in image encryption, using Hadamard product matrix permutation, index permutation and four-dimensional pixel diffusion algorithms, and finally generates the ciphertext image. The method of biaxial coupling can construct six different types of chaotic systems, after image encryption, the average value of information entropy reaches 7.9994, the correlation coefficient is close to 0, the NPCR and UACI are close to the ideal values of 99.61 % and 33.46 %, the algorithm can effectively resist the statistical attack, the robustness attack and the differential attack, and the results demonstrate that the algorithm has better security performance. © 2024 The Author(s)

In the field of secure communications, the robustness of cipher images transmitted in various channels is becoming increasingly important. In this paper, a robust image encryption algorithm combining a new chaotic system and discrete cosine transform is proposed, which is interlinked with plain information and is resistant to high-intensity noise attacks. First, a 5D continuous hyperchaotic system is proposed, leading to an interrelated sequence of five chaotic sequences. Second, the plain image is subjected to discrete cosine transform. Then the transform domain image is quantized, and some high-frequency components are removed, and then the high-frequency components are filled with chaotic sequences. Next, the transform domain image is scrambled, and inverse discrete cosine transform is performed, and its gray value is mapped to obtain a spatial domain image. Finally, the spatial image is scrambled by the spiral transformation, and then the diffusion operation is performed to obtain the encrypted image. Through the simulation experiment, the histogram, correlation, differential attack, and robustness are analyzed. The experimental results show that the proposed encryption algorithm can resist high-intensity noise attacks and has good encryption performance.

随着科学技术的发展,图像的应用越来越广泛,所带来的安全问题也越来越多,保护图像信息的安全是人们面临的一项严峻任务。通过对混沌系统和各种图像加密算法的学习研究,提出了一种基于优化后的Arnold置乱算法和扩散算法的图像加密算法。检测结果表明,该加密算法具有较快的加/解密速度、较高的安全性和优良的加密效果,能很好地保护图像信息安全,避免信息泄露。

超宽带无线通信技术是一种使用窄脉冲为信息载体的高速宽带接入技术,具有对信道衰落不敏感,发射信号功率谱密度低,抗检测性好,系统技术复杂度低,定位准确等优点。由于超宽带信号具有非常低的功率谱密度,因此可以通过频谱重叠共享的方式与现有窄带系统实现共存,但超宽带系统中采用的伪随机序列具有一定的周期性,因此使得发射信号功率谱中存在较多周期性的离散谱线,对其他系统产生潜在干扰的同时也易被第三方检测到。利用数字混沌序列代替周期的伪随机序列,可以达到信号能量均匀化,平滑功率谱密度,减小系统间干扰的目的,同时数字混沌序列的初值敏感性可提高系统的保密性。本文提出一种基于混沌矩阵的复合混沌序列生成方法,利用混沌矩阵进行二次混沌映射,降低混沌序列中存在的弱周期现象,并据典型混沌序列的统计特性,生成多进制数字混沌序列,并对数字混沌序列的复杂度和随机性进行分析比较。利用多值数字混沌序列对超宽带脉冲信号进行调制,平滑发射信号的功率谱密度,降低对其它无线系统的干扰,在ARCH模型下分析发射信号的频域不可预测性,同时对系统的抗检测性进行比较分析。仿真结果标明,本文提出的基于复合混沌序列的混沌超宽带系统具有较好的频域随机性,与传统超宽带信号相比,具有强的抗检测性。

This article proposes an image encryption algorithm based on a chaotic bit-plane decomposition and optimization algorithm of a crossover operator artificial bee colony algorithm. Firstly, use the SHA-256 hash algorithm to calculate the plaintext image's hash value as the starting value of the fractional Lorenz hyperchaotic system after operation. Utilize the chaotic sequence to permutate plaintext image in a bit plane to obtain the scrambled image. Secondly, block the scrambled image into four subimages of equal size, and count the hash value of each row of each block by the SHA-256 hash algorithm as the starting value of the Sine-Tent-Logistic chaotic system. Use the obtained chaotic sequence to substitute the images. Then, stitch the four sub-block images to get the final encrypted image, and the population is obtained. Finally, use the information entropy of ciphertext image as the fitness function of the artificial bee colony algorithm based on a crossover operator. Select the ciphertext image with the best information entropy from the population as the optimal encrypted image, and then, return the position value of the best honey source meanwhile. The experimental simulation and security analysis indicate that the scheme has an excellent encryption effect and ability to oppose various general attacks.

在科技发展的时代,实时通信已经成为必不可少的交流手段,信息安全成为人们担心的问题。目前,大部分混沌图像加密算法都是基于耗散系统,密码破译者可利用耗散系统的混沌吸引子进行分析破译。本文提出了基于位平面和保守混沌系统的图像加

In this paper, a novel fractional-order conservative system is constructed. The new system has rich dynamical behaviors by the consequence of the data simulation findings. The change of a certain parameter value can make system produce a range of conservative flows with varying topologies, and modifying further parameters the conservative flows can exhibit extension, expansion, and rotational tendencies. The initial offset behavior, extreme multi-stability, as well as multiple transient transition phenomena, can be observed. It is worth noting that two special phenomena are discovered in the paper: one is the discovery of hyperchaos in this system, which has never been reported before in the study of fractional-order conservative systems; the other is the existence of dissipation in this conservative system, which can be manifested by altering the order or parameter. These phenomena are analyzed in detail by utilizing phase diagram, bifurcation diagram, the Lyapunov exponent spectra and time series diagram. Over and above, we also analyze the feasibility of the system being used as a pseudo-random sequence generator. At last, the hardware implementation of the system is carried out on the DSP experimental platform to verify the correctness of theoretical analysis. The results show that this system has potential practical application value.

On the basis of ensuring the quality and concealment of steganographic images, this paper proposes a double-matrix decomposition image steganography scheme with multi-region coverage, to solve the problem of poor extraction ability of steganographic images under attack or interference. First of all, the cover image is transformed by multi-wavelet transform, and the hidden region covering multiple wavelet sub-bands is selected in the wavelet domain of the cover image to embed the secret information. After determining the hidden region, the hidden region is processed by Arnold transform, Hessenberg decomposition, and singular-value decomposition. Finally, the secret information is embedded into the cover image by embedding intensity factor. In order to ensure robustness, the hidden region selected in the wavelet domain is used as the input of Hessenberg matrix decomposition, and the robustness of the algorithm is further enhanced by Hessenberg matrix decomposition and singular-value decomposition. Experimental results show that the proposed method has excellent performance in concealment and quality of extracted secret images, and secret information is extracted from steganographic images attacked by various image processing attacks, which proves that the proposed method has good anti-attack ability under different attacks.

In response to the problems of high complexity and the large amount of operations of existing color image encryption algorithms, a low-complexity, low-operation color image encryption algorithm based on a combination of bit-plane and chaotic systems is proposed that is interrelated with plaintext information. Firstly, three channels of an RGB image are extracted, and the gray value of each pixel channel can be expressed by an eight-bit binary number. The higher- and lower-four bits of the binary gray value of each pixel are exchanged, and the position of each four-bit binary number is scrambled by a logistic chaotic sequence, and all the four-bit binary numbers are converted into hexadecimal numbers to reduce the computational complexity. Next, the position of the transformed image is scrambled by a logistic chaotic sequence. Then, the Chen chaos sequence is used to permute the gray pixel values of the permuted image. Finally, the gray value of the encrypted image is converted into a decimal number to form a single-channel encrypted image, and the three-channel encrypted image is synthesized into an encrypted color image. Through MATLAB simulation experiments, a security analysis of encryption effects in terms of a histogram, correlation, a differential attack, and information entropy is performed. The results show that the algorithm has a better encryption effect and is resistant to differential attacks.