A visually secure multiple image encryption using chaotic map and compressive sensing is proposed. The existing image encryption algorithms transform a secret image into a random noise like cipher image which can lead to cryptanalysis by an intruder. In the proposed method, compressive sampling is done using a chaos based, key controlled measurement matrix. An image dependent key generation scheme is used to generate the parameters of the chaotic map. The secret images are transformed into wavelet coefficients, and scrambled along a zigzag path, so that the high correlation among them can be reduced and thereby provide increased security level. The sparse coefficients are measured using the chaotic map-based measurement matrix, whose initial parameters are obtained from the keys generated. Then the reduced measurements are embedded into the sub-bands of the wavelet transformed cover image. Therefore, the proposed algorithm is highly sensitive to the secret images and can effectively withstand known-plaintext and chosen-plaintext attacks. Additionally, the cipher image and the secret images are of same size and do not require additional transmission bandwidth and storage space.
相似文献In this paper, a new image encryption algorithm is introduced for encrypting grayscale digital images of any size. To improve the encryption evaluation parameters, we suggested that the value of the plain image correlation coefficient be effective in the cryptographic process, so plain images with different properties and correlation coefficient rates are encrypted in different ways. According to the average absolute value of correlation coefficient of plain image, Logistic or Tent maps is selected to generate chaotic sequences to expand plain image matrix. As the first step of the diffusion phase, the plain image matrix is developed with larger size by proper selected chaotic sequences, and simultaneously a chaotic matrix with the same size is generated by chaotic Sine map sequences. In confusion phase, the modified Lorenz map changes pixel locations of new developed matrix by means of certain equations. Then bitwise XOR is applied between developed matrix include plain image and Sine map chaotic matrix, as second step of diffusion phase. Finally, encrypted image is generated after applying exchange operations on the content of pixels, as third step of diffusion phase. Experimental results and comparisons with some of the existing methods, show that the proposed image cryptosystem is able to resist common cryptanalytic attacks and can be used as a secure method for encrypting digital images.
相似文献For a gray image, every row (column) can be seen as an irregular wave. Activated by the architecture of permutation-diffusion based image encryption scheme, a chaotic image encryption algorithm is proposed to change the representation of irregular waves in the plain-image. To reduce the high correlation, permutation for both rows and columns is taken in the first stage. Due to the transposition of pixels in row/column, wave shapes will be changed according to the pseudo-random sequences generated from chaotic map. Specifically, pixels in each wave (row or column) are divided into two groups by energy (a bigger one and a smaller one). Then different groups are employed to manipulate the production of chaotic sequence. As a result, the chosen-plaintext and known-plaintext attacks will be difficult due to the plain-image dependent keystream. In the second stage, wave-by-wave diffusion in column is carried out such that any tiny change in the plain-image spreads out uniformly to the whole cipher-image. The keystream used in diffusion is designed again dependent on the permuted image obtained from the first stage. In this way, the security of the proposed algorithm can be further strengthened compared with some existing algorithms. Related security analyses also show that our method can satisfy common requirements of secure communication for daily images.
相似文献Recent years have seen a rapid evolution of digital communications and an immense use of image transmissions over unsecured links. More specifically, some domains require the exchange of images depicting sensitive information, such as fingerprints, medical records and government or military satellite images. This creates a major challenge for researchers to come up with efficient and effective image encryption schemes. On the other hand, chaotic maps have proven suitable for such applications. This is because they exhibit characteristics such as ergodicity and sensitivity to control parameters and initial conditions. In this paper, an image encryption confusion-diffusion technique is proposed. First, the image pixels are disarranged resulting in a shuffled one which is then diffused through XORing its pixels with a secret key. This key is generated from a combination of different chaotic maps. Performance of the proposed scheme is evaluated utilizing various metrics. The proposed scheme is shown to be robust against differential attacks and resistant to statistical attacks. Its running time is very small which guarantees its efficiency and suitability for real time applications.
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