Geng Zhao

Chaos-based image encryption scheme combining DNA coding and entropy

Information security has became more and more important issue in modern society, one of which is the digital image protection. In this paper, a secure image encryption scheme based on logistic and spatiotemporal chaotic systems is proposed. The extreme sensitivity of chaotic system can greatly increase the complexity of the proposed scheme. Further more, the scheme also takes advantage of DNA coding and eight DNA coding rules are mixed to enhance the efficiency of image confusion and diffusion. To resist the chosen-plaintext attack, information entropy of DNA coded image is modulated as the parameter of spatiotemporal chaotic system, which can also guarantee the sensitivity of plain image in the encryption process. So even a slight change in plain image can cause the complete change in cipher image. The experimental analysis shows that it can resistant different attacks, such as the brute-force attack, statistical attack and differential attack. What’s more, The image encryption scheme can be easily implemented by software and is promising in practical application.

Privacy Preserving Face Identification in the Cloud through Sparse Representation

Nowadays, with tremendous visual media stored and even processed in the cloud, the privacy of visual media is also exposed to the cloud. In this paper we propose a private face identification method based on sparse representation. The identification is done in a secure way which protects both the privacy of the subjects and the confidentiality of the database. The face identification server in the cloud contains a list of registered faces. The surveillance client captures a face image and require the server to identify if the client face matches one of the suspects, but otherwise reveals no information to neither of the two parties. This is the first work that introduces sparse representation to the secure protocol of private face identification, which reduces the dimension of the face representation vector and avoid the patch based attack of a previous work. Besides, we introduce a secure Euclidean distance algorithm for the secure protocol. The experimental results reveal that the cloud server can return the identification results to the surveillance client without knowing anything about the client face image.

Color Image Encryption in CIE L*a*b* Space

To protect the contents of images in the mobile internet era during image storage and transmission, image encryption has achieved a tremendous success during the last decades. Currently, little attention has been paid to non-RGB color spaces such as HSV, YUV and L*a*b* color spaces in the color image encryption community. In this paper we use high level encryption schemes in more informative channels and low level encryption schemes in less informative channels. This paper is the first time to encrypt color image in CIE L*a*b* color space. First we convert RGB to L*a*b* color space. The 2D Arnold’s cat map followed by the 3D Lu chaotic map are conducted in the L* channel. The less complicated DNA coding and 1D logistic map based encryption scheme is leveraged in the a* and b* channels, which contain less information than that in the L* channel. The experimental results reveal that our method achieves similar results with the method that conducts the same scheme in each channel of the RGB color space, while consuming less time. In addition, our method can resistant several attacks such as brute-force attack, statistic attack, correlation attack.

An Image Encryption Algorithm Based on Zigzag Transformation and 3-Dimension Chaotic Logistic Map

An image encryption algorithm based on Zigzag transformation and 3-Dimension Logistic chaotic map by making use of the permutation-diffusion encryption structure is proposed. The algorithm consists of two parts: firstly, Zigzag transformation is used to scramble pixel position of the color image through three channels; then, 3-Dimension Logistic chaotic map is utilized to diffuse pixel values through three channels. To solve the problem of large computation and space overhead of color image encryption algorithm, the iterative chaotic sequences are used several times in the diffusion process to improve encryption efficiency. The key space of the algorithm is large enough to resist brute-force attack and simulation results show that it also has high key sensitivity, high encryption speed and the strong ability to resist exhaustive attack and statistical attack.

A Survey of Chaos-Based Cryptography

As an offshoot of dynamical systems, chaos is highly sensitive to initial conditions and exhibits seemingly random behavior. From the perspective of cryptography and information security, randomness generated from entirely deterministic systems is a very appealing property. Chaotic cryptography has experienced significant developments since its birth in the early 90s. During these years, numerous research achievements have been obtained. This paper will present an overview about chaos-based cryptography and relevant progress that covers the main techniques used in this field.

An invertible and anti-chosen plaintext attack image encryption method based on DNA encoding and chaotic mapping

With the rapid development of network, more and more digital images need to be stored and communicated. Due to the openness and network sharing, the problems of digital image security become an important threat In this paper, we propose a novel gray image encryption algorithm based on chaotic mapping and DNA (Deoxyribonucleic Acid) encoding. We solve the error of irreversibility of a previous work, which can only encrypt the plain image, and cannot decrypt the cipher image with the correct secret key and can be attacked by the chosen plaintext. To make the algorithm invertible, we encode the input gray image by DNA encoding and generate a random matrix based on the logistic chaotic mapping. The DNA addition operation is conducted on the random matrix follow by the DNA complement operation guided by a random binary matrix generate by 2 logistic chaotic mapping sequences. We solve the problem of the irreversibility successfully. In addition, the algorithm can now resistant the several attacks such as chosen plaintext attack, brute-force attack, and statistic attack.

Color image encryption in YCbCr space

Nowadays, with the development of Internet technology and the improvement of safety awareness, image encryption technique has become very important, especially for color image encryption. The direction of research is focused on the RGB color space. There are few researches in other color spaces, such as HSV, L*a*b*, YCbCr. In this paper, we propose a color image encryption method in YCbCr color space. There is much information in Y channel but little information in Cb and Cr channel. Using this feature, we choose different encryption schemes. We first convert the color space from RGB to YCbCr. Then we encrypt the three channels separately. In Y channel, with Arnold cat map, we can do the preliminary image confusion, and then we use three-dimensional Lu chaotic map to do the further image diffusion. In Cb and Cr channels, we use DNA encoding and 1D Logistic chaotic map. Experimental results show that our color image encryption works well, our method in YCbCr space can compare with the RGB and L*a*b* space, and can resist brute-force attacks, differential attacks. The most prominent point is that the speed of encryption and decryption is much faster.

Object Image Relighting through Patch Match Warping and Color Transfer

In this paper, we propose a novel method for image based object relighting through patch match warping and color transfer. According to our method, a pair of reference object images (A and B), without any knowledge of the 3D geometry or material information of the input object image, are needed. The input image has similar illumination condition as that of the reference image A. The reference image B has the target illumination condition. We first modify the color of the reference object images according to the color of the input object image. Then the modified reference image A is warped to the input image using the image patch match. The reference B has the same warping to that of A. At last, the illumination of the reference B is transferred to the input image through a local and global transfer model learned from the warped reference B and A. We test our method on the ALOI dataset (Amsterdam Library of Object Images) and acquire convincing relit result on numerous input and reference object images with different illumination conditions.

Novel two dimensional discrete chaotic maps and simulations

This paper introduces one new novel 2-dimensional quadric polynomial discrete chaotic map and seven novel triangle function combination discrete chaotic maps (2D-TFCDM). The 2D-TFCDMs have at least one positive Lyapunov exponent. Extensive numerical simulations display the orbits of the 2D-TFCDMs to have different chaotic attractors.

Color image encryption in non-RGB color spaces

To protect the contents of images in the mobile internet era during image storage and transmission, image encryption has achieved a tremendous success during the last decades. Traditional color image encryption method often use the RGB color space. We have the observation that in non-RGB color spaces, the luminance channels often contain more information for content recognition than the chroma channels do. Thus, in this paper we propose to use high level encryption schemes in more informative channels and low level encryption schemes in less informative channels. The 2D Arnold’s cat map followed by the 3D Lu chaotic map are conducted in the luminance channel. The less complicated DNA coding and 1D logistic map based encryption scheme is leveraged in the chroma channels. We use this strategies in 4 typical non-RGB color spaces, i.e., YCbCr, YIQ, HSV, L*a*b*. We evaluate and compare the performances and the time consumptions of the methods in the 4 Non-RGB color spaces. The experimental results reveal that the encryption methods in Non-RGB color spaces can achieve similar results as the method that conducts the same encryption level in each channel of the RBG color space, including the resistance to several attacks such as brute-force attack, statistic attack, correlation attack, while consuming less time. The method in YCbCr color space performances the best in the time consumption.