Cryptanalysis of Chen et al.’s multi-secret visual cryptography scheme

Abstract

In a (k, n) visual cryptographic scheme (VCS), a secret image is encrypted into n shadow images in such way that any k or more shadows can be superimposed to visually decode the secret, and less than k shadows cannot obtain any information on the secret image. Most VCSs only share one secret image. A (k, n, s) multi-secret VCS (MVCS) is a (k, n)-VCS, which can share s secret images. Recently, Chen et al. introduced a novel (2, 2, 4)-MVCS. However, their scheme is insecure. The threshold property of Chen et al.’s (2, 2, 4)-MVCS is compromised. In this paper, we show how an attacker retrieves the secret information of Chen et al.’s (2, 2, 4)-MVCS from one shadow image.     

Secret image transmission based on VQ and data embedding

A new secret image transmission scheme suitable for narrow communication channel is proposed in this article. A set of secret images can be simultaneously and efficiently delivered to the receiver via a small and meaningless data stream by the proposed scheme. To reduce the volume of secret images, a codebook is first generated and these secret images are encoded into binary indexes based on the vector quantization (VQ) technique. The compressed message is then embedded into the VQ codebook utilized in the encoding procedure by an adaptive least‐significant‐bits (LSB) modification technique. For the purpose of security, the slightly modified codebook is further encrypted into a meaningless data stream by the AES cryptosystem. Simulation results show that the proposed scheme provides an impressive improvement both in the visual quality of the extracted secret images at the receiver and in the hiding capacity of the cover medium. Experimental data also reveal the feasibility of the proposed secret image transmission scheme for limited‐bandwidth environment. © 2007 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 17, 1–9, 2007     

Colour visual cryptography schemes

Visual cryptography scheme (VCS) is a kind of secret-sharing scheme which allows the encryption of a secret image into n shares that are distributed to n participants. The beauty of such a scheme is that, the decryption of the secret image requires neither the knowledge of cryptography nor complex computation. Colour visual cryptography becomes an interesting research topic after the formal introduction of visual cryptography by Naor and Shamir in 1995. The authors propose a colour (k, n)-VCS under the visual cryptography model of Naor and Shamir with no pixel expansion, and a colour (k, n)-extended visual cryptography scheme ((k, n)-EVCS) under the visual cryptography model of Naor and Shamir with pixel expansion the same as that of its corresponding black and white (k, n)-EVCS. Furthermore, the authors propose a black and white (k, n)-VCS and a black and white (k, n)-EVCS under the visual cryptography model of Tuyls. Based on the black and white schemes, the authors propose a colour (k, n)-VCS and a colour (k, n)-EVCS under the same visual cryptography model, of which the pixel expansions are the same as that of their corresponding black and white (k, n)-VCS and (k, n)-EVCS, respectively. The authors also give the experimental results of the proposed schemes, and compare the proposed scheme with known schemes in the literature.     

Pixel expansion-free grey-scale image sharing method

Abstract

In recent years, many visual secret sharing technologies have been proposed to protect the security of secret images (black and white, grey scale or colour images). In 2005, Lukac and Plataniotis used the concept of the Naor–Shamir method to propose a visual secret sharing technology for sharing secret grey-scale images based on bit-plane decomposition. Although their method can avoid pixel-value cutting problem, it still suffers from the pixel expansion problem. In this paper, we propose a new secret grey-scale image sharing method to improve this situation. In the proposed sharing image creation phase, two sharing images (one is grey-scale and the other is binary) are created and later shared by two protectors. The original secret image can be easily reconstructed if both sharing images are obtained. However, one cannot obtain the original secret image from each of the sharing images. Experimental results also show that the proposed method can effectively solve the pixel expansion problem.     

Toward a secure protection scheme for visual secret sharing

Visual cryptography, proposed by Naor and Shamir in 1995, is a scheme which decodes messages by using human visual sensitivity. Cheating has been proved to be possible in visual cryptography. We propose a cheating prevention scheme which precludes members of a group from collusive cheating by using additional images for verification. In each pair of shared images, we detect cheating by mutually verification. The result of verification is clear and directly perceived by the senses. It is a practical technique using authenticating images while the structure of the secret is complex.     

Hiding a secret colour image in two colour images

Abstract

Visual cryptography is different from traditional cryptography. That is, neither time-consuming computation nor complex cryptographic knowledge is needed. Stacking is the only operation required to recover a secret image, and the individual image does not give the hackers any information about the secret image. None of researches tried to deal with meaningful colour share transparencies. Hence, two methods are proposed for hiding a colour image in two meaningful colour share transparencies in this paper. To achieve this goal, the colour decomposition approach and halftone technology are first applied to cope with secret colour images. Then the concept of the human visual system is utilized to generate two colour meaningful sharing transparencies. To support various applications, two variants are presented. The first proposed method, method-1, is suitable for simple colour images, and the second, method-2, provides better visibility of complex colour images.     

A GLCM-Feature-Based Approach for Reversible Image Transformation

Recently, a reversible image transformation (RIT) technology that transforms a secret image to a freely-selected target image is proposed. It not only can generate a stego-image that looks similar to the target image, but also can recover the secret image without any loss. It also has been proved to be very useful in image content protection and reversible data hiding in encrypted images. However, the standard deviation (SD) is selected as the only feature during the matching of the secret and target image blocks in RIT methods, the matching result is not so good and needs to be further improved since the distributions of SDs of the two images may be not very similar. Therefore, this paper proposes a Gray level co-occurrence matrix (GLCM) based approach for reversible image transformation, in which, an effective feature extraction algorithm is utilized to increase the accuracy of blocks matching for improving the visual quality of transformed image, while the auxiliary information, which is utilized to record the transformation parameters, is not increased. Thus, the visual quality of the stego-image should be improved. Experimental results also show that the root mean square of stego-image can be reduced by 4.24% compared with the previous method.     

Digital image watermarking based on VSS in BTC domain

Abstract

An image watermarking model based on visual secret sharing (VSS) is proposed for protection of ownership. In the embedding phase, the watermark is first divided by VSS into two parts: a hiding watermark and a secret watermark. Then only the hiding watermark is embedded into the original image and the secret watermark is reserved for watermark extracting by the owner. In the extracting phase, the hiding watermark is extracted from the watermarked image first and then directly superimposed on the secret watermark to recover the watermark information.     

A Weighted Threshold Secret Sharing Scheme for Remote Sensing Images Based on Chinese Remainder Theorem

The recent advances in remote sensing and computer techniques give birth to the explosive growth of remote sensing images. The emergence of cloud storage has brought new opportunities for storage and management of massive remote sensing images with its large storage space, cost savings. However, the openness of cloud brings challenges for image data security. In this paper, we propose a weighted image sharing scheme to ensure the security of remote sensing in cloud environment, which takes the weights of participants (i.e., cloud service providers) into consideration. An extended Mignotte sequence is constructed according to the weights of participants, and we can generate image shadow shares based on the hash value which can be obtained from gray value of remote sensing images. Then we store the shadows in every cloud service provider, respectively. At last, we restore the remote sensing image based on the Chinese Remainder Theorem. Experimental results show the proposed scheme can effectively realize the secure storage of remote sensing images in the cloud. The experiment also shows that no matter weight values, each service providers only needs to save one share, which simplifies the management and usage, it also reduces the transmission of secret information, strengthens the security and practicality of this scheme.     

Greyscale image encoding and watermarking based on optical asymmetric cryptography and variational image decomposition

In this paper, a novel greyscale image encoding and a watermarking scheme based on optical asymmetric cryptography and variational image decomposition (VID) are proposed. In this proposed scheme, the greyscale watermark is encoded into a noise-like pattern by the phase-truncated Fresnel transform (PT-FrT)-based optical asymmetric cryptography. The greyscale host image is decomposed into its cartoon part and texture part by the VID technique. After that, the encoded watermark is embedded into the host image’s texture part by a discrete wavelet transform (DWT) based fusion approach. The proposed scheme can achieve a better watermark invisibility and a higher robustness by embedding the watermark into the host image’s texture part. Additionally, the proposed scheme can achieve a high security, because the PT-FrT-based optical asymmetric cryptography can resist some common cryptographic attacks. The feasibility, robustness and security of the proposed scheme have been demonstrated by extensive experiments and comparison with other relevant image encoding and watermarking schemes.     

Improved security in the genetic algorithm-based image steganography scheme using Hilbert space-filling curve

This paper presents the security analysis of a recently proposed data hiding scheme by Kanan and Nazeri [A novel image steganography scheme with high embedding capacity and tunable visual image quality based on a genetic algorithm. Expert Syst Appl. 2014;41(14):6123–6130]. Security of the scheme depends upon a secret key\chromosome constructed using a genetic algorithm. The key specifies offsets and patterns for data embedding. By performing the key-sensitivity analysis and exploiting image pixel correlation, it is shown in the present paper that the secret data can be easily revealed. Simulation results demonstrate that just 11 bits out of the 27-bit secret key are sufficient to reveal the data. To overcome the problem, an improvement is suggested in the data embedding pattern that demonstrates high data security. Bitwise analysis of the secret key used in the modified approach exhibits high sensitivity to change in the key.     

Hierarchical secret image sharing using phase modulation based on the Fresnel transform

ABSTRACT

In idealized secret image sharing (SIS), all of the shared images (shadows) play the same role, but in real life, the shared images are often hierarchical. This paper proposes a hierarchical secret image sharing (HSIS) method by means of optical imaging. To implement the scheme, a generalized single-phase modulation algorithm is proposed in Fresnel transform domain. Its features that multiple secret images can be recovered through combination of some shared images though each participant only holds one share of images. Theoretically, the secret images are divided into multiple phase encodings (shared images) by phase modulation, each secret image can be directly captured by the intensity detector when illuminating some of the shared images orderly displayed with parallel light. Experimental simulation shows that the shared images and the restored secret images do not have any size distortion, and further verifies the feasibility of the proposed scheme.     

Reversible Data Hiding in Encrypted Image Based on Block Classification Permutation

Recently, reversible data hiding in encrypted image (RDHEI) has attracted extensive attention, which can be used in secure cloud computing and privacy protection effectively. In this paper, a novel RDHEI scheme based on block classification and permutation is proposed. Content owner first divides original image into non-overlapping blocks and then set a threshold to classify these blocks into smooth and non-smooth blocks respectively. After block classification, content owner utilizes a specific encryption method, including stream cipher encryption and block permutation to protect image content securely. For the encrypted image, data hider embeds additional secret information in the most significant bits (MSB) of the encrypted pixels in smooth blocks and the final marked image can be obtained. At the receiver side, secret data will be extracted correctly with data-hiding key. When receiver only has encryption key, after stream cipher decryption, block scrambling decryption and MSB error prediction with threshold, decrypted image will be achieved. When data hiding key and encryption key are both obtained, receiver can find the smooth and non-smooth blocks correctly and MSB in smooth blocks will be predicted correctly, hence, receiver can recover marked image losslessly. Experimental results demonstrate that our scheme can achieve better rate-distortion performance than some of state-of-the-art schemes.     

叉车造型的视觉动力分析及其意象仿生设计研究

目的 为了提升叉车外观造型,增强市场竞争力,满足用户的感性意象需求,需要通过意象仿生设计提升叉车的情感内涵.方法 通过视觉动力分析,综合考虑理性与感性视觉意象进行设计.首先采用语义差分法获得叉车的目标意象,建立意象与叉车动力式样之间的关联,并利用层次分析法得到叉车关键造型部位的权重排序;其次利用生物特征作为意象感知介质,渲染目标意象氛围.结论 将可识别的生物特征匹配设备的关键造型部位,形成的备选方案可满足用户意象需求,评价筛选后得到最优方案.该意象仿生设计流程期望能够对相关工程车辆造型设计提供借鉴.     

一种基于YC-rC-b颜色空间和视觉特性的彩色图像水印技术

根据图像离散余弦变换频谱图特征及结合人眼对亮度和颜色的对比度敏感视觉特性,提出了一种人眼感知图像最小误差即JND阈值的计算方法,通过计算出的JND阈值,提出了一种基于YCrCb颜色空间的彩色图像水印技术方案。方案依据JND阈值筛选彩色图像的3个分量亮度图变换域频谱系数来进行水印的嵌入和提取。从水印技术方案上看,JND阈值的引入使得水印的嵌入达到最大;嵌入算法使得水印嵌入的位置具有随机性,有力地保证了水印信息的安全性。仿真实验和攻击测试表明:含水印图经压缩攻击后的图像与原始图像基本一样,提取的水印信息与原始水印基本相同;攻击后的含水印图具有较好的透明性和较高的鲁棒性。提出的基于YCrCb颜色空间和人眼视觉特性的彩色图像水印技术方案,是一种可行的、较好的彩色图像技术。     

一种基于视觉感兴趣区域的彩色图像增强方法

目的把视觉感兴趣区域概念引入直方图的建造中,提出了一种新的基于视觉感兴趣区域的图像增强方法,使增强效果更符合人眼视觉感知。方法首先在标准观测环境下利用先进的眼动仪设备获得人眼感兴趣区域,然后计算各子区域的平均显著值,以确定各个子区域的权重系数,最后采取类似直方图均衡化的思想,优化配比灰度级的动态范围。结果通过主客观实验结果表明,增强后的图像更符合人眼视觉感知。结论结合了视觉感知特性的直方图增强方法,弥补了传统直方图与人眼视觉感知不一致的弊端,其增强效果更佳。     

Modified transform-based gamma correction for MRI tumor image denoising and segmentation by optimized histon-based elephant herding algorithm

Medical image processing is typically performed to diagnose a patient's brain tumor prior to surgery. In this study, a technique in denoising and segmentation was developed to improve medical image processing. The proposed approach employs multiple modules. In the first module, the noisy brain tumor image is transformed into multiple low- and high-pass tetrolet coefficients. In the second module, multiple low-pass tetrolet coefficients are applied through a modified transform-based gamma correction method. Generalized cross-validation is used on multiple high-pass tetrolet coefficients to obtain the best threshold value. In the third module, all enhanced coefficients are applied to the partial differential equation method. In the final module, the denoised image is applied to Atanassov's intuitionistic fuzzy set histon-based fuzzy clustering method with centroid optimization using an elephant herding method. Accordingly, the tumor part is segmented from the nontumor part in the magnetic resonance imaging brain images. The method was assessed in terms of peak signal-to-noise ratio, mean square error, specificity, sensitivity, and accuracy. The experimental results showed that the suggested method is superior to traditional methods.     

一种新的基于可逆矩阵的具有完整性检验能力的图像加密方案

为了保护图像信息的安全,论文利用组合理论知识,提出一种新的基于可逆整数矩阵的、具有完整性检验能力的图像加密方案。应用该方案将一个灰度图像加密生成一个脆弱的噪声密图,解密过程是加密的简单逆过程。密图的完整性可以凭借人类视觉系统进行检验,不需要任何复杂的计算。当密图遭受恶意篡改时,解密得到一个噪声图,无法得到原始图像的任何信息。论文加密方案的密钥简单,且密钥空间足够大。理论分析和实验结果证明了,该方案为图像加密提供了一种高安全性和有效的机制。