Implementation of TiOISSS with meaningful shadows and with an additional authentication image

Visual Cryptography Scheme (VCS) is a cryptographic technique for protecting secret images. The advantage of using VCS is that decoding can be done without use of any computations. Nevertheless, the reconstructed image has poor visual quality. Therefore, Two in One Image Secret Sharing Scheme (TiOISSS) was proposed which takes the advantage of VCS and provides good quality decoded images. However, the existing TiOISSS has security limitations as it is implemented only for noisy shadows. Hence, in this paper, modified TiOISSS is proposed and implemented for meaningful shadows. To enhance the security of the shares and prevent fake shares that may be introduced by hackers, an authentication image is shared along with the secret image. The quality of the reconstructed image is improved by using adaptive halftoning technique. Experimental results demonstrate the improved security and quality by the proposed scheme.     

Enhanced hybrid image security algorithms for high definition images in multiple applications

Protection of multimedia information from different types of attackers has become important for people and governments. A high definition image has a large amount of data, and thus, keeping it secret is difficult. Another challenge that security algorithms must face with respect to high definition images in medical and remote sensing applications is pattern appearances, which results from existing regions with high density in the same color, such as background regions. An encryption and hiding based new hybrid image security systems are proposed in this paper for the purpose of keeping high definition images secret. First, one hiding method and two encryption methods are used in two hybrid algorithms. The new hiding algorithm proposed here starts by applying reordering and scrambling operations to the six Most Significant Bit planes of the secret image, and then, it hides them in an unknown scene cover image using adding or subtracting operations. Second, two different ciphering algorithms are used to encrypt the stego-image to obtain two different hybrid image security systems. The first encryption algorithm is based on binary code decomposition, while the second algorithm is a modification of an advanced encryption standard. After evaluating each hybrid algorithm alone, a comparison between the two hybrid systems is introduced to determine the best system. Several parameters were used for the performance, including the visual scene, histogram analysis, entropy, security analysis, and execution time.

     

基于图像分存的离散小波数据隐藏算法

数字图像分存技术将一幅秘密图像分解成几幅无意义或者杂乱无章的图像进行存储或传输,获得其中部分分存信息就能恢复出原始图像信息,以便增加图像信息的安全性.文中提出了一种基于图像分存和离散小波变换的的信息隐藏算法.首先利用置乱变换对传输图像进行加密,再将置乱后的隐秘信息分成N份,然后将隐秘信息随机嵌入到图像的小波分解系数中,...     

A blind watermarking algorithm based on fractional Fourier transform and visual cryptography

This paper presents a robust copyright protection scheme based on fractional Fourier transform (FrFT) and visual cryptography (VC). Unlike the traditional schemes, in our scheme, the original image is not modified by embedding the watermark into the original image. We use the visual secret sharing scheme to construct two shares, namely, master share and ownership share. Features of the original image are extracted using SVD, and are used to generate the master share. Ownership share is generated with the help of secret image (watermark) and the master share, using VC technique. The two shares separately give no information about the secret image, but for ownership identification, the secret image can be revealed by stacking the master share and the ownership share. In order to achieve the robustness and security, the properties of VC, FrFT and SVD are used in our scheme. The experimental results show that the proposed scheme is strong enough to resist various signal processing operations.     

Secure Image Hiding Scheme Based on Magic Signet

Image data hiding technology is secret communications that carry hidden data in such a way that no one except the sender and intended recipients can even realize there is a hidden message. High embedding capacity, good images quality, and security are three important essentials. In this paper, each confidential hexadecimal will be carried by two cover pixels based on a magic matrix generated from a square template to reach the goal of higher embedding capacity while keeping good image visualization. Experimental results reveal that the proposed scheme guarantees higher embedding capacity of 2 bits per pixel and has the peak signal-to-noise ratio (PSNR) of 44.7 dB on average. Moreover, secret keys are used to ensure security consideration.     

Secret Sharing Using Visual Cryptography

Compared with the traditional cryptography,visual cryptography(VC) decrypts secret images referring to the characteristics of human vision,rather than the cryptography knowledge or complex computations.Furthermore,seeing to the freeness of the secret key,the whole process of encryption as well as decryption for the visual cryptography meets a fast dealing course.As to the security concern,it is able to guarantee that no one can have access to any clues about the content of a secret image from individual cover images.Thus,owing to the studies on this area,the target of light-weighted cryptography is reached.Now the visual cryptography has been developed from the meaningless shadows to the meaningful ones.Seeing to the highly developed technique,some advanced VC techniques are introduced in this survey,respectively.     

多重门限的图像秘密共享方案

 针对传统的基于视觉密码的图像秘密共享方案存在像素扩张导致其只能共享小尺寸的秘密图像、信息隐藏效率较低的问题,提出一种能够提高信息隐藏容量的(t,k,n)多重门限图像秘密共享方案.该方案利用秘密图像信息控制视觉密码方案中共享矩阵的选取,从而实现秘密图像在视觉密码方案中的隐藏.在秘密图像恢复的第一阶段,任意t个参与者直接叠加其影子图像后可以视觉解密出低质量的秘密图像信息;在第二阶段,任意k个参与者可以从影子图像中提取出隐藏的信息,并通过计算恢复出精确的灰度秘密图像.相对于传统的视觉密码方案,本文方案在不影响视觉密码恢复图像的视觉质量前提下,可以隐藏更多的秘密图像信息,而像素扩张尺寸较小.     

SPREAD: Improving network security by multipath routing in mobile ad hoc networks

We propose and investigate the SPREAD scheme as a complementary mechanism to enhance secure data delivery in a mobile ad hoc network. The basic idea is to transform a secret message into multiple shares, and then deliver the shares via multiple paths to the destination so that even if a certain number of message shares are compromised, the secret message as a whole is not compromised. We present the overall system architecture and discuss three major design issues: the mathematical model for the generation and reconstruction of the secret message shares, the optimal allocation of the message shares onto multiple paths in terms of security, and the multipath discovery techniques in a mobile ad hoc network. Our extensive simulation results justify the feasibility and the effectiveness of the SPREAD approach.

No embedding: A novel image cryptosystem for meaningful encryption

In this paper, we propose a novel image cryptosystem, which enables to encrypt the secret images with a smaller-size cover image. Compared with the existing meaningful encryption methods, our cryptosystem has three advantages: (1) non-embedding encryption, i.e., there isn’t any data embedding into the cover image during the encryption process. (2) Our cryptosystem can simultaneously encrypt multiple secret images with one cover image, which greatly improves the security of secret images. (3) Our cryptosystem can accomplish not only the meaningful encryption, but also the meaningless encryption. Thus, people don’t switch encryption methods when meeting different encryption requirements. Our scheme leverages the popular coupled dictionary learning and compressive sensing techniques to accomplish the whole task. Specifically, we use the coupled dictionaries to build connection between the cover image and the secret image, and apply the compressive sensing to decrypt the secret image. To demonstrate the effectiveness of the proposed cryptosystem, a series of experiments are conducted. Experimental results on gray images and colorful RGB images verify its superiority.     

Adaptive data hiding in palette images by color ordering and mapping with security protection

Palette images are widely used in multimedia and Internet applications. In this paper, a new method for data hiding in palette images with security protection by color ordering and mapping, as well as parameter randomization, is proposed. First, image pixels are classified as data embeddable or nonembeddable, and only the former ones are used to embed secret data. The proposed idea of data hiding is based on the use of a new type of color-ordering relationship, from which a color-mapping function is defined with binary values as output. When a secret data bit is to be embedded, a data-embeddable pixel is selected, and its color is adjusted to make the output of the color-mapping function equal to the secret bit value. The embedded secret data can be extracted correctly and quickly from the resulting stego-image by merely inspecting the outputs of the color-mapping function. Indetectability of the secret information embedded by the proposed method is also analyzed and confirmed. Furthermore, a number of possible security enhancement measures based on parameter randomization in the data-embedding process are proposed to protect the hidden data in the stego-image. The randomization effect is created by the use of a secret key and a number of random number-generating functions. The proposed data hiding method was tested with a variety of palette images. The experimental results show that secret data can be embedded and extracted successfully without producing visual artifacts in the cover image. A good balance between stego-image quality and data-embedding capacity can be achieved, which proves the efficiency and feasibility of the proposed method for practical applications.     

具有掩盖图像的（2，2）可视密码方案

为解决传统可视密码像素膨胀及分存图像无意义等问题,文中提出了一个具有掩盖图像的（2,2）可视密码方案。方案中密图为黑白反色图像,利用半色调技术将两个灰度图像处理后的半色调图像作为掩盖图像,根据密图修改掩盖图像生成分存图像,叠加分存图像恢复密图。方案符合可视密码解密简单的特性且分存图像有意义,没有引入任何像素膨胀。     

Cheating in (halftone-secret) visual cryptography: Analysis of blind authentication schemes

In visual cryptography (VC), cheating is an important security concern where dishonest participants will fool honest ones and make them accept a fake secret by providing fake shares. Share and blind authentications are two categories of cheating prevention, and the last one relies on the inherent robust of shares against cheating attacks. In the previous studies, cheating in VC only focuses on operating a ‘pixel block’ instead of a region of adjacent pixels. However, the well-known advantage of VC is to decode the secret image by using the human vision system (HVS), so it leads to a natural issue to reconsider cheating a region. In this paper, we formally address the binocular cheating attack (BCA) for a region to augment effectiveness of original cheating for a block. Finally, we demonstrate how to realize BCA by presenting non-trivial techniques against some blind authentication schemes, and further obtain implausible results. The BCA can also be applied to halftone secret.     

A new framework for particle detection in low-SNR fluorescence live-cell images and its application for improved particle tracking

Image denoising and signal enhancement are two common steps to improve particle contrast for detection in low-signal-to-noise ratio (SNR) fluorescence live-cell images. However, denoising may oversmooth features of interest, particularly weak features, leading to false negative detection. Here, we propose a robust framework for particle detection in which image denoising in the grayscale image is not needed, so avoiding image oversmoothing. A key to our approach is the new development of a particle enhancement filter based on the recently proposed particle probability image to obtain significantly enhanced particle features and greatly suppressed background in low-SNR and low-contrast environments. The new detection method is formed by combining foreground and background markers with watershed transform operating in both particle probability and grayscale spaces; dynamical switchings between the two spaces can optimally make use the information in images for accurate determination of particle position, size, and intensity. We further develop the interacting multiple mode filter for particle motion modeling and data association by incorporating the extra information obtained from our particle detector to enhance the efficiency of multiple particle tracking. We find that our methods lead to significant improvements in particle detection and tracking efficiency in fluorescence live-cell applications.     

Grey-level image hiding scheme based on vector quantisation

A novel image hiding scheme capable of hiding multiple grey-level images into another grey-level cover image is proposed. To reduce the volume of secret images to be embedded, the vector quantisation scheme is employed to encode the secret images. The compressed message is then encrypted by the DES cryptosystem to ensure security. Finally, the encrypted message is hidden into the cover image using the greedy least significant bit substitution technique.     

Secret image communication scheme based on vector quantisation

A novel secret image communication scheme capable of delivering several images by a small cover medium is proposed. To reduce the volume of secret images to be delivered, a codebook is generated and the secret images are compressed based on the VQ encoding system. The compressed message is then embedded into the VQ codebook by an adaptive least-significant-bits modification technique. Finally, the slightly modified codebook is encrypted into a meaningless data stream by the DES cryptosystem for security.     

多级秘密信息隐藏方法

针对普通的一级秘密信息隐藏的方法具有安全性低,视觉效果差的问题,本文提出了一种多级别信息隐藏的方法.该方法使一级秘密信息在一级密钥作用下成为宿主图像,提高了信息隐藏的安全性,再将宿主图像分成3×3的图像块,在二级密钥的控制下成功将二级秘密信息嵌入.采用图像置乱和LSB算法的结合方法,并在两级秘密信息的作用下,使得载密图...     

多分存彩色图像秘密共享（2，n）方案

文献[2]中提出了一种基于异或（XOR）操作的彩色图像秘密共享（2,n）方案,简单易于实现,但恢复密图的效果较差。通过分析此方案,文章提出一个多分存的彩色图像秘密共享（2,n）方案,通过给用户增加分存图像的方法改善了恢复密图的质量。实验分析表明所提方案不仅取得了很好的恢复效果,而且保持了安全性和算法的简单性。     

基于Bernstein多项式的数字图像分存

数字图像分存技术将一幅秘密图像分解成为几幅无意义或者杂乱无章的图像进行存储或传输,以便增加图像信息的安全性.本文讨论了数字图像分存技术及其在信息安全中的应用,首先利用置乱变换对传输图像进行加密,然后利用Bernstein多项式对加密图像进行分存,并可以无误差的恢复出原图像.     

High-capacity reversible data hiding in encrypted images based on adaptive block encoding

This paper proposes a new high-capacity reversible data hiding scheme in encrypted images. The content owner first divides the cover image into blocks. Then, the block permutation and the bitwise stream cipher processes are applied to encrypt the image. Upon receiving the encrypted image, the data hider analyzes the image blocks and adaptively decides an optimal block-type labeling strategy. Based on the adaptive block encoding, the image is compressed to vacate the spare room, and the secret data are encrypted and embedded into the spare space. According to the granted authority, the receiver can restore the cover image, extract the secret data, or do both. Experimental results show that the embedding capacity of the proposed scheme outperforms state-of-the-art schemes. In addition, security level and robustness of the proposed scheme are also investigated.