快速置乱耦合3D混沌映射的图像加密算法研究

针对当前3D混沌映射加密算法的安全性不高,且其置乱过程的计算量大,置乱性不稳定,以及置乱方法不具有通用性等缺陷,设计了一种快速通用置乱方法,并将混淆与扩散机制同时引入进来,提出了一种新的3D混沌映射图像加密算法。首先利用快速置乱方法置乱初始图像,以改变像素位置;利用三维Chen系统结合像素值变换函数所生成初始外部密钥迭代3D混沌映射,得到一个序列,该序列根据混淆机制对置乱图像像素值进行混淆;改变外部密钥,再迭代计算3D混沌映射,得到三元一维伪随机数组,并借助密钥流机制量化该数组,得到新序列,利用该新序列根据扩散机制对混淆后的像素进行扩散处理。借助MATLAB仿真软件对该算法及其他3D算法进行对比仿真。结果显示:与其他3D算法相比,该算法安全性更高,置乱速度更快,计算效率更高,且其密钥空间巨大。     

Bit level image encryption algorithm based on hyperchaotic system

Because chaotic systems are unpredictable, ergodic and sensitive to initial values and parameters, they are often used in the field of encryption. To avoid the bad randomness of the random key generated by the low dimensional chaotic map system, a 5-dimensional multi-wing hyperchaotic system is adopted in this paper. The key stream generated by the chaotic system is related to the plaintext image. So it can effectively resist the attacks of selecting plaintext. The plaintext graph is decomposed into binary form by bit plane decomposition technique, and then these bit planes are divided into high and low groups. The designed control matrix is used to identify the specific scrambling mode, and each bit is permuted within and between groups. Finally, bit diffusion is used to change the pixel value of each pixel. Theoretical analysis and numerical simulation show that the algorithm has good encryption performance for image encryption.     

基于变步长约瑟夫遍历和DNA动态编码的图像加密算法的安全性分析

近年来,不断有新的图像加密算法被提出,其安全性却未得到充分的分析和验证。该文对一种最新报道的图像加密算法的安全性进行了分析。所分析算法通过基于变步长约瑟夫遍历的像素置乱、基于DNA动态编码的像素替换及像素行列扩散来完成图像加密。分析表明,该算法的秘密密钥设计不具有实用性,加密过程也存在缺陷。在选择明文攻击条件下,对该算法的加密过程进行了密码分析,并提出了相应的攻击算法。仿真实验和理论分析确认了所提攻击算法的有效性与可行性。最后,针对所分析算法及部分图像加密算法中存在的问题,提出了改进建议。     

基于超混沌系统和密文交错扩散的图像加密新算法

该文提出一种基于超混沌系统优化序列并结合密文交错扩散的并行图像加密策略。首先,对超混沌序列进行改造使得改进序列更适合图像加密;然后,利用改进的混沌序列产生与明文相关的最终密钥序列,使得算法对明文敏感。图像被分成两个子块,以并行方式对子块进行两轮像素加密,并引入密文交错扩散技术。对密钥空间和执行效率、像素分布特性、相关系数、抗差分攻击能力以及密钥敏感性进行了测试和分析,证明了方案的安全性和执行效率。结果表明,该算法安全高效,在图像保密通信中具有较大的应用潜力。     

Novel SCAN-CA-based image security system using SCAN and 2-D von Neumann cellular automata

This paper presents a novel SCAN-CA-based image security system which belongs to synchronous stream cipher. Its encryption method is based on permutation of the image pixels and replacement of the pixel values. Permutation is done by scan patterns generated by the SCAN approach. The pixel values are replaced using the recursive cellular automata (CA) substitution. The proposed image encryption method satisfies the properties of confusion and diffusion as the characteristics of SCAN and CA substitution are flexible. The salient features of the proposed image encryption method are lossless, symmetric private key encryption, very large number of secret keys, key-dependent permutation, and key-dependent pixel value replacement. Simulation results obtained using some color and gray-level images clearly demonstrate the strong performance of the proposed SCAN-CA-based image security system.     

基于混沌集的图像加密算法

该文提出一种基于包含离散混沌系统、连续混沌系统的混沌系统集的混沌加密算法,该加密算法可以根据加密强度需求选择不同的混沌系统组合,利用图像像素的像素均值及像素坐标值为参数控制混沌密钥产生,增强混沌密钥与明文数据之间的联系。在加密基础上,将密文按位切割成3个数据后伪装隐藏在一个处理后的公开图像内,改变了密文外观特性。通过对加密后的图像进行图像直方图分析、相邻像素相关性分析及图像信息熵分析,表明该加密算法有效,在图像保密传输中具有应用潜力。     

An Intelligent Session Key-Based Hybrid Lightweight Image Encryption Algorithm Using Logistic-Tent Map and Crossover Operator for Internet of Multimedia Things

Due to the increasing demand for IoMT applications in numerous fields such as healthcare, smart city, smart grids, industrial internet, etc. The privacy and security become a major issue in front of various researchers working in this field. This work proposed a lightweight image encryption algorithm based on a logistic-tent map and crossover operator of a genetic algorithm. Various 1-D chaotic maps are discussed in the literature review, but in some cases, hybrid 1-D chaotic maps have higher performance than simple 1-D chaotic maps. So 1-D chaotic map along with a crossover operator is used in this work. Here logistic-tent map and crossover are used to generate the random session key for each image encryption. Also, a crossover operator is used in encryption rounds for increasing confusion and diffusion. Here in this work, for each image encryption, a new intelligent session key is generated. The strength of the proposed image cryptographic scheme is assessed against resistance to the differential attack (UACI and NPCR), statistical attack (histogram analysis, correlation coefficient and information entropy) and sensitivity to the secret key. The extensive experiments of performance and security assessment show that the proposed cryptographic image scheme is secure enough to withstand all potential cryptanalytic attacks.

     

基于变步长约瑟夫遍历和DNA动态编码的图像加密算法

数字图像传输和存储的安全问题已成为信息安全研究的热点。该文提出一种基于变步长约瑟夫遍历和DNA动态编码的图像加密方法。首先将混沌映射产生的随机序列作为约瑟夫遍历的变步长，改进约瑟夫遍历问题，并采用改进的约瑟夫遍历对图像像素位置进行置乱；其次，动态选择DNA编码规则，对图像像素进行DNA编码，并与给定的DNA序列进行碱基运算；DNA编码规则的动态选择，很好地解决了DNA编码规则少所带来的安全隐患，提高了算法的安全性。最后通过密文反馈和混沌系统迭代来进一步增强算法的混淆和扩散特性。实验和安全性分析结果表明，该算法不仅对密钥的敏感性强，而且能有效抵御统计性分析和穷举分析等攻击操作。     

通用数字图像加密与抗剪切攻击恢复算法

为对数字图像进行有效地保护,提出一种以混沌系统及其混沌序列为基础的通用加密与解密算法。首先,根据密钥产生一个混沌序列,经排序后生成相应的下标序列,并据此进行像素坐标置乱加密。然后,根据子密钥与图像类型值由混沌序列生成相应的无符号整数序列,并按顺序与对应的像素值进行异或运算以实现像素值置换加密。针对恶意剪切攻击,同时提出一种基于邻域相邻像素特性的抗剪切攻击恢复算法。实验结果与理论分析表明,该算法加密效果好,密钥空间大,安全性与通用性强,且具有较为理想的抗统计分析攻击与抗剪切攻击能力。     

改进约瑟夫遍历和分段Logistic映射的图像加密算法

为了满足网络通信和图像传输的安全,提出了一种改进约瑟夫遍历和分段Logistic映射的图像加密算法,在置乱过程中通过改进约瑟夫遍历对待加密图像进行全局像素置乱,将置乱像素按照矩阵排列,分解成两个四位的高低矩阵,低四位矩阵利用分段的Logistic混沌映射进行加密处理,对高四位矩阵通过异或运算改变原来矩阵,再将两个四位矩阵结合起来得到加密图像。改进的约瑟夫遍历可以有效抵御周期性攻击,分段Logistic映射引入图像的元素值增强了秘钥的独特性,实验结果证明,该加密算法秘钥空间大,安全性能好,可以抵御穷举,直方图统计等各种攻击。     

一种带扰动的高维混沌图像加密算法

针对已有的部分混沌加密算法存在的问题,设计了一个带有扰动的高维混沌图像加密算法。通过对三维Lorenz系统添加扰动改善了序列的随机性,引入了三维猫映射对扩散后的图像进行置乱,并通过二次置乱来提高算法的安全性。分析与仿真结果表明,该算法具有较大的密钥空间,加密后图像像素值分布较均匀,相关系数接近于零,可以有效抵抗已知明文攻击。     

Color image encryption using one-time keys and coupled chaotic systems

This paper proposes a color image encryption scheme using one-time keys based on coupled chaotic systems. The key stream has both the key sensitivity and the plaintext sensitivity. The Secure Hash Algorithm 3 (SHA-3) is employed to combine with the initial keys to generate the new keys, to make the key stream change in each encryption process. Firstly, the SHA-3 hash value of the plain image is employed to generate six initial values of the chaotic systems. Secondly, combine and permute the six state variables, and randomly select three state variables from them, to encrypt the red, green and blue components, respectively. Experimental results and security analysis show that the scheme can achieve good encryption result through only one round encryption process, the key space is large enough to resist against common attacks, so the scheme is reliable to be applied in image encryption and secure communication.     

A fast encryption algorithm of color image based on four-dimensional chaotic system

As the low complexity of low-dimensional chaotic system and the slow speed of image encryption, this paper proposes a fast encryption algorithm of color image based on four-dimensional chaotic system. Firstly, we propose a new method of designing four-dimensional chaotic system based on the classical equations of three-dimensional chaotic system, to increase the complexity and key space of the encryption algorithm. Secondly, according to the nature of color images’ pixels channel, we design a new pseudo-random sequence generator and reuse the random sequence, to improve the speed of image encryption. Finally, the methods of row-major and column-major are used to diffuse the original image and the cat map with parameter is used to scramble the image pixels, respectively, to achieve the effect of encryption. The results of simulation and security analysis show that the proposed encryption algorithm is of good performance on security, robustness and high encryption speed.     

基于激光散斑和超混沌的彩色图像加密

为了保证彩色图像在传输过程中的安全性与可靠 性,提出将具有随机性的激光散斑与一种四维 Lorenz型超混沌系统相结合进行彩色图像加密的新方法,同时构建了散斑超混沌加密系统。 系统将原始彩图 与超混沌系统产生的非线性度更高的超混沌序列按位异或进行混沌加密,然后将加密后的图 像与物理随机 的激光散斑图像按位异或进行散斑加密即可获得加密彩图,密钥空间达10¹⁰¹,平均相邻像素相关系数达 0.000。结果表明,本文方法具有较好的加密 效果,可抵御统计分析攻击,有大的密钥空间,较强的密钥敏 感性及弱的相邻像素相关性。     

基于组合混沌系统的彩色视频流加密算法

为进一步加强视频图像在存储及传输过程中的安全性,提出一种将两种改进的混沌系统和分组加密算法结合的彩色视频流加密方案.将原视频逐帧提取并取其RGB分量,并用改进的logistic混沌系统控制其高低位进行各分量位重组.再利用级联式二维猫映射,对亮度分量R实现快速空域置乱;通过改进型二维logistic映射构造的非线性混沌序列,对色度分量GB分量进行迭代扩散.然后将已加密的三分量通过AES算法进行二重加密.算法利用了高低维混沌的空域混合双重加密.仿真结果表明该算法的解密图像无损、无失真,具有更好的密钥敏感性、更好的安全性.     

A new S-box construction method based on the fractional-order chaotic Chen system

Since substitution box (S-box) is the only nonlinear component related to confusion properties for many block encryption algorithms, it is a necessity for the strong block encryption algorithms. S-box is a vital component in cryptography due to having the effect on the security of entire system. Therefore, alternative S-box construction techniques have been proposed in many researches. In this study, a new S-box construction method based on fractional-order (FO) chaotic Chen system is presented. In order to achieve that goal, numerical results of the FO chaotic Chen system for \(a= 35, b=3, c=28\) and \(\alpha =0.9\) are obtained by employing the predictor–corrector scheme. Besides, a simpler algorithm is suggested for the construction of S-box via time response of the FO chaotic Chen system. The performance of suggested S-box design is compared with other S-box designs developed by chaotic systems, and it is observed that this method provides a stronger S-box design.     

Improved algorithm for image encryption based on DNA encoding and multi-chaotic maps

New image encryption based on DNA encoding combined with chaotic system is proposed. The algorithm uses chaotic system to disturb the pixel locations and pixel values and then DNA encodings according to quaternary code rules are carried out. The pseudo DNA operations are controlled by the quaternary chaotic sequences. At last the image encryption through DNA decoding is achieved. The theoretical analysis and experimental results show that the algorithm improves the encoding efficiency, enhances the security of the ciphertext, has a large key space and a high key sensitivity, it is able to resist the statistical and exhaustive attacks.     

Application of quantum genetic algorithm in high noise laser image security

Aiming at the security problem of range gated laser imaging in high noise background, a range gated laser image encryption scheme based on the quantum genetic algorithm(QGA) is proposed. Due to the fuzziness of the laser image itself, the randomness and security of the key become more and more important in encryption. In this paper, the chaotic sequence is used as the parent chromosome of the QGA, and the random number satisfying the encryption algorithm is obtained by an iterative genetic algor...     

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.     

基于神经网络混沌吸引子的混合加密

把Diffe-Hellman密钥交换协议和流密码算法相结合,设计了一种基于神经网络混沌吸引子的混合加密算法。算法采用基于混沌吸引子的Diffe-Hellman公钥体制,保证了密钥分发的安全性,同时拥有流密码速度快的优点,提高了加密速度,因此实用性较好,能够满足下一代通信实时快速的需求。分析了算法的安全性和加解密效率,利用vc编程实现算法,并对仿真生成的密钥流和密文进行测试。实验结果表明,算法具有较好的安全性和加解密速度。