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401.
一种光电器件加密方法的安全性分析 总被引:1,自引:1,他引:0
为了找到一种安全、高速的图像加密方法,通过计算明文和密文的信息熵、灰度值等参数,研究了利用光电器件,采用流密码和位平面分解相结合的加密方法的安全性和该方案的抗破译能力。结果表明,该方案中, 对含信息量越少的图像,加密后平均灰度变化值越大;这种灰度变换的加密方法掩盖了各像素点之间的相关性,密文像素点灰度随机分布,分析者无法获得明文图像的灰度分布状况,使得分析者无法通过相关度分析提取图像轮廓,有效隐藏重要信息。因此,该加密方法具有极高的安全性,同时应将密文平均灰度值作为评价参数之一。 相似文献
402.
《Communications in Nonlinear Science & Numerical Simulation》2014,19(10):3653-3659
Many round-based chaotic image encryption algorithms employ the permutation–diffusion structure. This structure has been found insecure when the iteration round is equal to one and the secret permutation of some existing schemes can be recovered even a higher round is adopted. In this paper, we present a single round permutation–diffusion chaotic cipher for gray image, in which some temp-value feedback mechanisms are introduced to resist the known attacks. Specifically, we firstly embed the plaintext feedback technique in the permutation process to develop different permutation sequences for different plain-images and then employ plaintext/ciphertext feedback for diffusion to generate equivalent secret key dynamically. Experimental results show that the new scheme owns large key space and can resist the differential attack. It is also efficient. 相似文献
403.
In this paper, we propose an image encryption technique to simultaneously encrypt double or multiple images into one encrypted image using computational integral imaging (CII) and fractional Fourier transform (FrFT). In the encryption, each of the input plane images are located at different positions along a pickup plane, and simultaneously recorded in the form of an elemental image array (EIA) through a lenslet array. The recorded EIA to be encrypted is multiplied by FrFT with two different fractional orders. In order to mitigate the drawbacks of occlusion noise in computational integral imaging reconstruction (CIIR), the plane images can be reconstructed using a modified CIIR technique. To further improve the solution of the reconstructed plane images, a block matching algorithm is also introduced. Numerical simulation results verify the feasibility and effectiveness of the proposed method. 相似文献
404.
Xiaopeng Yan 《中国物理 B》2022,31(8):80504-080504
We present a new cosine chaotic mapping proved by chaos theory test and analysis such that the system has good cryptography properties, wide chaos range, simple structure, and good sensitivity to initial value, and the mapping can meet the needs of chaotic image encryption. Based on the cosine chaotic system, we propose a new encryption method. First, according to the cyclic characteristics of the mapping, the cyclic information wave is simulated. Second, the quasi-Doppler effect is used to synchronously scramble and diffuse the image to obfuscate the original pixel. Finally, the XOR diffusion of image pixels is carried out by information wave to further enhance the encryption effect. Simulation experiment and security analysis show that the algorithm has good security, can resist the common attack mode, and has good efficiency. 相似文献
405.
Xiao-Gang Wang 《中国物理 B》2022,31(9):94202-094202
The two types of nonlinear optical cryptosystems (NOCs) that are respectively based on amplitude-phase retrieval algorithm (APRA) and phase retrieval algorithm (PRA) have attracted a lot of attention due to their unique mechanism of encryption process and remarkable ability to resist common attacks. In this paper, the securities of the two types of NOCs are evaluated by using a deep-learning (DL) method, where an end-to-end densely connected convolutional network (DenseNet) model for cryptanalysis is developed. The proposed DL-based method is able to retrieve unknown plaintexts from the given ciphertexts by using the trained DenseNet model without prior knowledge of any public or private key. The results of numerical experiments with the DenseNet model clearly demonstrate the validity and good performance of the proposed the DL-based attack on NOCs. 相似文献
406.
Finite-time complex projective synchronization of fractional-order complex-valued uncertain multi-link network and its image encryption application 下载免费PDF全文
Yong-Bing Hu 《中国物理 B》2022,31(11):110501-110501
Multi-link networks are universal in the real world such as relationship networks, transportation networks, and communication networks. It is significant to investigate the synchronization of the network with multi-link. In this paper, considering the complex network with uncertain parameters, new adaptive controller and update laws are proposed to ensure that complex-valued multilink network realizes finite-time complex projective synchronization (FTCPS). In addition, based on fractional-order Lyapunov functional method and finite-time stability theory, the criteria of FTCPS are derived and synchronization time is given which is associated with fractional order and control parameters. Meanwhile, numerical example is given to verify the validity of proposed finite-time complex projection strategy and analyze the relationship between synchronization time and fractional order and control parameters. Finally, the network is applied to image encryption, and the security analysis is carried out to verify the correctness of this method. 相似文献
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410.
This Letter proposes two different attacks on a recently proposed image based on hyper-chaos. The cryptosystem under study proceed first by shuffling the image rows and columns to disturb the high correlation among pixels by iterating the logistic map. Second, a keystream is generated to mix it with the pixels of the shuffled image using hyper-chaos. These two processes in the encryption stage present weakness, and a chosen plaintext attack and a chosen ciphertext attack can be done to recover the ciphered-image without any knowledge of the key value. It just demands three couples of plaintext/ciphertext to break totally the cryptosystem. 相似文献