整合ChaCha20哈希运算的分块扩散自适应图像加密算法

目的 针对数字图像网络传输安全性和混沌加密算法自适应差的问题,提出一种基于ChaCha20哈希运算的分块扩散自适应图像加密算法(BDCH)。方法 BDCH算法首先通过分段线性混沌映射(PWLCM)产生的混沌序列填充明文图像,使其成为方形图像;其次,利用初始输入密钥及明文图像总和,通过ChaCha20哈希运算生成8×8的初始哈希矩阵,并与PWLCM混沌映射生成的伪随机序列作用,联合产生哈希密钥矩阵,PWLCM的迭代初值选取为初始密钥矩阵均值、初始密钥及明文图像归一化均值;然后,利用Arnold和PWLCM映射同步置乱扩散整幅图像,并分成互不重叠的8×8大小图像块;最后,采用哈希密钥矩阵对图像块进行两轮扩散,完成图像加密。结果 灰度及彩色图像的计算机仿真与性能分析表明,BDCH算法的信息熵、峰值性噪比、密钥敏感性指标优于其他加密算法,并且解决了直接使用初始哈希矩阵会产生的弱密钥问题,密钥空间大。结论 结合同步置乱扩散和哈希密钥矩阵非线性分块扩散的BDCH算法可有效抵抗各种攻击,安全性高、自适应性强,适合各种类型的灰度及彩色图像加密,潜在应用价值大。     

一种基于高维混沌系统的彩色图像加密新算法

根据高维混沌系统具有更高安全性的特点,提出一种基于统一混沌系统和广义猫映射的彩色图像加密新算法。该算法先利用广义猫映射分别实现空域彩色图像三基色置乱变换,然后由统一混沌系统输出的三维混沌序列分别实现空域彩色图像三基色逐像素替代变换。研究结果表明,该算法具有良好的像素值混淆、扩散性能和较大的抵抗强力攻击的密钥空间,加密图像像素值具有类随机均匀分布特性,且相邻像素的值具有零相关特性,证明了所提出方案具有较高的安全性。     

基于动态密钥的彩色图像扩散加密算法

为提高图像加密算法的安全性,提出一种基于动态密钥的彩色图像扩散加密算法.对彩色图像的三通道图像采用Hilbert曲线和Arnold矩阵对每一像素点进行随机置乱,计算与加密密钥关联的待加密图像特征值,调整扩散序列,扰动扩散过程,实现可变控制参数的图像加密,有效解决同一加密系统中不同图像加密时加密过程中参数不变的规律性问题...     

基于动态网络的非线性置乱扩散同步图像加密

具有置乱-扩散结构的传统图像加密中的置乱与扩散通常相互独立,易被单独针对破解,且加密过程非线性弱,导致算法安全性差,为此提出了一种具有强非线性的置乱扩散同步图像加密算法.首先,构造新型sine-cos混沌映射,以拓宽控制参数范围,并改善序列分布的随机性;然后,用明文像素与混沌序列的异或和作为混沌初始值产生混沌序列,用其...     

基于四维超混沌系统的彩色图像加密算法

针对彩色图像在加密过程中数据量大、相邻像素相关性强及冗余度高等缺陷,提出基于新四维超混沌的彩色图像加密算法.利用混沌性能更好的四维超混沌系统与反向传播神经网络结合进行序列融合运算,生成伪随机性更好的融合序列作为密钥流;利用密钥流对彩色图像像素块进行位置置乱及像素扩散运算,得到最终的密文图像.仿真计算结果表明,该加密算法...     

A lightweight image encryption scheme based on chaos and diffusion circuit

Multimedia Tools and Applications - The Internet of Things (IoT) devices is being deployed in almost all aspects of human life starting from smart home, health monitoring, smart metering, to smart...     

扩散映射置乱与超混沌系统组合图像加密算法

提出一个基于扩散与位平面Arnold映射相结合的彩色图像置乱,以及采用Chen系统产生的混沌序列加密的图像加密算法。先由Logistic系统构造的二维非线性动力系统产生的混沌序列形成扩散矩阵和Arnold映射矩阵,然后在基色上对彩色图像进行扩散,并在不同的位平面对彩色图像进行置乱,最后用Chen系统产生的混沌序列对置乱后的图像进行加密。该算法实现简单,能够抵御多种攻击,且容易用硬件实现。     

二维离散分数阶Fourier变换的双混沌图像加密算法

针对现今分数阶Fourier变换和传统混沌加密的不足,提出了一种基于二维离散分数阶Fourier变换的双混沌图像加密算法。该算法首先借助明文图像信息生成辅助密钥矩阵与输入密钥相结合得到混沌序列,再将生成的中间密文作为二维离散分数阶Fourier变换输入,最后进行置乱操作,使得明文信息得到很好的隐藏。通过实验仿真表明,该算法不仅能有效抵抗统计特征攻击、差分攻击,而且大大改善经传统分数阶Fourier变换后直方图像不平滑的缺点,达到很好的加密效果。     

A novel image encryption based on hash function with only two-round diffusion process

In this paper, a novel algorithm for image encryption based on hash function is proposed. In our algorithm, a 512-bit long external secret key is used as the input value of the salsa20 hash function. First of all, the hash function is modified to generate a key stream which is more suitable for image encryption. Then the final encryption key stream is produced by correlating the key stream and plaintext resulting in both key sensitivity and plaintext sensitivity. This scheme can achieve high sensitivity, high complexity, and high security through only two rounds of diffusion process. In the first round of diffusion process, an original image is partitioned horizontally to an array which consists of 1,024 sections of size 8 × 8. In the second round, the same operation is applied vertically to the transpose of the obtained array. The main idea of the algorithm is to use the average of image data for encryption. To encrypt each section, the average of other sections is employed. The algorithm uses different averages when encrypting different input images (even with the same sequence based on hash function). This, in turn, will significantly increase the resistance of the cryptosystem against known/chosen-plaintext and differential attacks. It is demonstrated that the 2D correlation coefficients (CC), peak signal-to-noise ratio (PSNR), encryption quality (EQ), entropy, mean absolute error (MAE) and decryption quality can satisfy security and performance requirements (CC <0.002177, PSNR <8.4642, EQ >204.8, entropy >7.9974 and MAE >79.35). The number of pixel change rate (NPCR) analysis has revealed that when only one pixel of the plain-image is modified, almost all of the cipher pixels will change (NPCR >99.6125 %) and the unified average changing intensity is high (UACI >33.458 %). Moreover, our proposed algorithm is very sensitive with respect to small changes (e.g., modification of only one bit) in the external secret key (NPCR >99.65 %, UACI >33.55 %). It is shown that this algorithm yields better security performance in comparison to the results obtained from other algorithms.     

A secure multi-stage one-round bit-plane permutation operation based chaotic image encryption

Currently, data security is a challenging task in any open source data transmission network. Basically, in most of the networks, images are used, hence security of images is a major challenging task. This paper proposes a combined hyper-chaos and chaos based encryption technique to secure images. In the method, one-round of diffusion and multi-stage bit-plane permutation operations are performed to obtain the better encryption results. The advantages of this scheme are that in one-round encryption operation, the proposed scheme can be realized easily and also confused largely. Apart from that the algorithm is simple as it uses simpler mathematical computations while attaining higher security such as higher key space, higher number of pixel changing rate, higher unified average changing intensity, and better correlation coefficient results. Moreover, hash based keys are used to resist the algorithm against chosen-plaintext and known-plaintext attacks. The security analysis and computer simulations show the good encryption results of the proposed scheme and strong resistivity to the widely used common attacks.

     

基于新混沌与矩阵卷积运算的彩色图像加密算法

针对彩色图像加密过程中出现的强相关性和高冗余问题,提出基于云模型的Fibonacci混沌系统与矩阵卷积运算的彩色图像加密算法。首先对彩色图像的R、G、B分量拼接图像像素点坐标变换置乱;然后将混沌序列值作为卷积核的输入值与像素值进行矩阵卷积运算,实现像素值置换;再与云模型Fibonacci混沌序列及前相邻像素值进行正反双向2次异或操作生成加密图像。实验分析表明,加密后的图像直方图更加平滑,像素分布均匀,图像相邻像素相关性低,加密图像RGB分量平均水平、垂直和对角相关系数分别为-0.0010,0.0016和0.0031,能够抵抗差分攻击、明文攻击、噪声攻击和剪切攻击等攻击实验,提出的新加密算法具有加密安全性高、抗干扰性高、鲁棒性强等特点。     

A chaotic permutation and diffusion based image encryption algorithm for secure communications

In this digital era, a huge amount of digital data is being generated, transmitted, and stored over the network. Images are widely searched, shared and uploaded which make them more vulnerable to the attackers. Therefore, image encryption has become the most widespread form of secure image communication. In recent past, a range of chaotic encryption schemes have been proposed for image encryption which suffers from low key space and high computational overhead. In this paper, the authors have proposed a secure image encryption technique based on 2D Baker’s map. In the proposed scheme a plain image is permuted first, based on a sequence of pseudo random number generated by 2D Baker’s map followed by diffusion process based on XORing. The strength of the proposed scheme is analyzed using the most well-known security test measures like NPCR, MSE, PSNR, UACI, correlation coefficient, Entropy etc. and the results demonstrate that the proposed scheme is resistive to various types of known attacks. The scheme runs on comparatively low computational overhead. Further, the results are compared with existing schemes.

     

A novel image encryption scheme based on multi-directional diffusion technique and integrated chaotic map

Neural Computing and Applications - In recent years, many researchers have used chaos maps to encrypt digital images due to their unpredictability, ergodicity, and sensitivity to initial values....     

基于高维超混沌系统和矩阵张量积的图像分组加密新算法

目前混沌加密算法主要存在三方面的不足:1)采用低维混沌序列造成混沌退化;2)采用的混沌系统结构过于简单;3)算法只依赖于混沌系统的结构和密钥。针对这些不足,提出一种新的图像分组加密算法。为了克服混沌退化,算法借助矩阵张量积将高维超混沌系统所产生混沌序列和一维混沌序列充分耦合,产生像素扩散矩阵。在此过程中,用明文信息控制扩散矩阵生成,使算法与明文相关,提高了算法的安全强度。     

A novel color image encryption algorithm based on DNA sequence operation and hyper-chaotic system

A new color image encryption algorithm based on DNA (Deoxyribonucleic acid) sequence addition operation is presented. Firstly, three DNA sequence matrices are obtained by encoding the original color image which can be converted into three matrices R, G and B. Secondly, we use the chaotic sequences generated by Chen's hyper-chaotic maps to scramble the locations of elements from three DNA sequence matrices, and then divide three DNA sequence matrices into some equal blocks respectively. Thirdly, we add these blocks by using DNA sequence addition operation and Chen's hyper-chaotic maps. At last, by decoding the DNA sequence matrices and recombining the three channels R, G and B, we get the encrypted color image. The simulation results and security analysis show that our algorithm not only has good encryption effect, but also has the ability of resisting exhaustive attack, statistical attack and differential attack.     

基于混沌的数字图像加密综述

为了进一步讨论和完善混沌在数字图像加密领域应用已经取得的成果和存在的问题,简述了该领域的发展历程,总结了混沌作用于图像置乱的两大主流设计思想,对图像置乱的理论基础和主流方案进行了讨论,分析了传统置乱加密算法的弱点和不足。给出了常用的混沌置乱方法,介绍了混沌作用于加密系统的一般思路和应用混沌进行加密时应注意的几个问题,提出了灰度替换和像素置乱算法的评估标准等新见解,并讨论了该领域的发展方向。     

Optimizing chaos based image encryption

Multimedia Tools and Applications - Due to its inherent properties such as sensitivity to initial condition, ergodicity and systematic parametrization chaos systems have been extensively used in...     

一种基于位平面的图像加密算法

在不移动像素情况下达到对图像进行加密目的,提出一种基于图像位平面的加密算法。按像素比特位对图像进行分解,得到图像位平面,再利用两个Logistic混沌系统构造二值矩阵与中间密钥矩阵对位平面执行置乱加密,最后将各个位平面叠加得到密文图像。