Showing papers on "Visual cryptography published in 2015"

Secure and Efficient Medical Image Transmission by New Tailored Visual Cryptography Scheme with LS Compressions

Abstract: Exchanging a medical image via network from one place to another place or storing a medical image in a particular place in a secure manner has become a challenge. To overwhelm this, secure medical image Lossless Compression LC schemes have been proposed. The original input grayscale medical images are encrypted by Tailored Visual Cryptography Encryption Process TVCE which is a proposed encryption system. To generate these encrypted images, four types of processes are adopted which play a vital role. These processes are Splitting Process, Converting Process, Pixel Process and Merging process. The encrypted medical image is compressed by proposed compression algorithms, i.e Pixel Block Short algorithm PBSA and one conventional Lossless Compression LC algorithm has been adopted JPEG 2000LS. The above two compression methods are used to separate compression for encrypted medical images. And also, decompressions have been done in a separate manner. The encrypted output image which is generated from decompression of the proposed compression algorithm, JPEG 2000LS are decrypted by the Tailored Visual Cryptography Decryption Process TVCD. To decrypt the encrypted grayscale medical images, four types of processes are involved. These processes are Segregation Process, Inverse Pixel Process, 8-Bit into Decimal Conversion Process and Amalgamate Process. However, this paper is focused on the proposed visual cryptography only. From these processes, two original images have been reconstructed which are given by two compression algorithms. Ultimately, two combinations are compared with each other based on the various parameters. These techniques can be implemented in the field for storing and transmitting medical images in a secure manner. The Confidentiality, Integrity and Availability CIA property of a medical image have also been proved by the experimental results. In this paper we have focused on only proposed visual cryptography scheme.

Secure data hiding using steganographic technique with Visual cryptography and watermarking scheme

Abstract: The Visual cryptography scheme (VCS) is a secure method that encrypts a secret image into shares. The key idea behind the proposed approach deals with information hiding in image using Zig-Zag scanning pattern which is more complex algorithm in Steganography again encrypted as shares by VC technique for embedding in separate host images to provide authentication for the VC shares which makes these secret shares invisible by embedding them into host images. The secret shares generated from VC encryption are watermarked into some host images using digital watermarking. Digital watermarking is used for providing the double security of image shares. The share is embedded into the host image using Least Significant Bit Insertion Technique (LSB). The scheme provides more secure and meaningful secret shares that are robust against a number of attacks. The performance of the proposed system is evaluated using peak signal to noise ratio (PSNR), histogram analysis and also numerical experimentation suggests that embedding time varies linearly with message length. The simulation results show that, the proposed system provides high level of security.

Visual Cryptography and Obfuscation: A Use-Case for Decrypting and Deobfuscating Information using Augmented Reality

Abstract: As new technologies emerge such as wearables, it opens up for new challenges, especially related to security and privacy. One such recent technology is smart glasses. The use of glasses introduces security and privacy concerns for the general public but also for the user itself. In this paper we present work which focus on privacy of the user during authentication. We propose and analyze two methods, visual cryptography and obfuscation for protecting the user against HUD and camera logging adversaries as well as shoulder-surfing.

Usability of Augmented Reality for Revealing Secret Messages to Users but Not Their Devices

Abstract: We evaluate the possibility of a human receiving a secret message while trusting no device with the contents of that message, by using visual cryptography (VC) implemented with augmented-reality displays (ARDs). In a pilot user study using Google Glass and an improved study using the Epson Moverio, users were successfully able to decode VC messages using ARDs. In particular, 26 out of 30 participants in the Epson Moverio study decoded numbers and letters with 100% accuracy. Our studies also tested assumptions made in previous VC research about users’ abilities to detect active modification of a ciphertext. While a majority of the participants could identify that the images were modified, fewer participants could detect all of the modifications in the ciphertext or the decoded plaintext.

Hiding secret message using visual cryptography in steganography

Abstract: This paper presents two layered security for data hiding by combining steganography and visual cryptography (VC). Classically, VC encrypts a secret image into noise like images called as shares and decrypts secret message by stacking of shares, whereas steganography hides secret into another image called as cover image, where only intended receiver decodes the message. Steganography often encodes secret message using secret key before hiding into another image. In this paper, cover message and encrypted secret message are encoded into noise-like shares using (2, 2) VC where concept of digital invisible ink of steganography is incorporated with VC (DIIVC) to hide secret message. Unlike typical steganography, shares are modified to conceal secret message instead of cover image. At receiver, decryption of shares using conventional VC results poor contrast cover image. Apparently, this result appears as sole secret disclosed using VC whereas only intended receiver has knowledge of secret message. Further, intended receiver retrieves encrypted secret message by applying proposed DIIVC algorithm on resultant cover image. Finally, original secret message is revealed using secret key.

Secret Sharing Using 3 Level DWT Method of Image Steganography Based on Lorenz Chaotic Encryption and Visual Cryptography

Abstract: Steganography is a traditional technique of covert communication. It is also best way to conceal secret data without revealing its existence to the outsider. In this paper a new technique of Image Steganography has been proposed which is using Lorenz Chaotic Encryption to encrypt the secret message, 3 level Discrete Wavelet Transform to hide encrypted data and visual cryptography to share stego image in secret communication.

Secured Document Sharing Using Visual Cryptography in Cloud Data Storage

Abstract: Security has emerged as the most concerned aspect of cloud computing environment and a prime challenge for the cloud users. The stored data can be retrieved by the user whenever and wherever required. But there is no guarantee that the data stored in the cloud server has not been accessed by any unauthorized user. The current cloud framework does not allow encrypted data to be stored due to the space and storage cost. Storing secret data in an unencrypted form is vulnerable to external attacks by both illegitimate customers and a Cloud Service Provider (CSP). Traditional encryption techniques require more computation and storage space. Hence, protecting cloud data with minimal computations is the prime task. Secured Document Sharing Using Visual Cryptography (SDSUVC) technique proposes an efficient storage scheme in a cloud for storing and retrieving a document file without any mathematical computations and also ensures data confidentiality and integrity.

Detection of phishing attack using visual cryptography in ad hoc network

Abstract: Mobile ad hoc networks (MANETs) provide a wide range of applications such as disaster relief, military application, wireless sensor network (WSN), education, entrainment, health, commercial and civilian environments. One of its important applications is in commercial and civilian environments that cover e-commerce, vehicular services and networks of visitors at airports. Nowadays, phishing attacks are increasing with burgeoning rate for e-commerce websites. This paper provides a novel anti-phishing approach based on visual cryptography. According to this approach a user generates two shares of an image using (2, 2) visual cryptography scheme. Client stores the first share of this image and second share is uploaded to the website at the time of user registration. After this, website asks for some other information like second share of the image, user name, and password. These credentials of a particular user can change once per login. During each login phase, a user verifies the legitimacy of a website by getting secret information with the help of stacking both shares. There are many existing approaches based on cryptographic technique but they all suffer from False Positive notification. However, proposed approach does not suffer from False Positive (FP) notification and outperforms all existing approaches.

A master share (2, n) XOR based visual cryptography scheme by random grids

Abstract: The rapid growth of internet applications and network users has made the processing of digital images via internet highly vulnerable. Existing random grid based visual cryptography schemes (RG-VCS) like any other visual cryptography schemes aim at imparting perfect secrecy and fast decryption without any complex computation. One among the several techniques in visual cryptography is the (2,n) RG-VCS which creates n shares with equal weightage and any of two shares out of n can be combined to recover the original image. The drawback of the existing system is that an attacker can recover the original image if he /she obtain any of the two shares created. The proposed system improves the security of (2, n) RG-VCS by incorporating the concept of a master share. The concept of a master share is introduced in such a way that recovery of the original image is possible if and only if one among the two shares combined is the master share. Decryption using any two shares from the remaining n-1 shares other than the master (i.e. client shares) reveals nothing. XOR-based decryption is implemented here as it seems to be a perfect candidate for (2, n) schemes which enhance the image quality of the recovered secret and solving alignment problems in visual cryptographic systems. There by the proposed work implemented a two-tier priority share model enhancing the confidentiality of visual cryptographic applications. Further, sufficient theoretical proofs are provided for the correctness of the implementation.

Visual Cryptography Based Lossless Watermarking for Sensitive Images

Abstract: Digital technology has resulted in a cost effective and easy means for storage and communication of the multimedia data, which can also be easily downloadable and reproducible. Hence, there is a growing need for techniques that identify the right owner of Intellectual Property (IP). Visual Cryptography based Lossless Watermarking (VCLW) techniques are hybrid schemes that are now being developed as a potential replacement for conventional watermarking systems as they are effective in resolving existing tradeoff among the requirements. This paper presents theoretical analysis of spatial domain VCLW techniques and performs practical performance analysis, to identify gaps. These hybrid techniques offer promising quality of target image after watermarking; there are still a number of challenges associated such as security, robustness, pixel expansion, complexity, image formats etc. Among multiple requirements, achieving fewer rates of false positives is identified as fundamental requirement in order to discourage malicious owners and to protect Intellectual Property. The analysis of comparative results shows that with the existing techniques, the false positive rate could not reach 10−6, which is the maximum limit suggested by Cox et al. for watermarking. This is due to the unique security challenge called C3 rule that involves the design of code tables, selection of features, thresholds and combination functions. It is concluded that in the applications where the images to be protected are very sensitive such as military, medical and satellite images, VCLW techniques can be a potential replacement for conventional watermarking systems, given that the algorithms fills the important gaps.

Online Payment System using Steganography and Visual Cryptography

Abstract: A rapid growth in E-Commerce market is seen in recent time throughout the world. With ever increasing popularity of online shopping, Debit or Credit card fraud and personal information security are major concerns for customers, merchants and banks specifically in the case of CNP (Card Not Present). This paper presents a new approach for providing limited information only that is necessary for fund transfer during online shopping thereby safeguarding customer data and increasing customer confidence and preventing identity theft. The method uses combined application of steganography and visual cryptography for this purpose. Keywords—Information security; Steganography; Visual Cryptography; Online shopping

A New Construction of Tagged Visual Cryptography Scheme

Abstract: Tagged visual cryptography scheme (TaVCS) is a new type of visual cryptography scheme, in which an additional tag image is revealed visually by folding up each share. A TaVCS not only carries augmented information in each share, but also provides user-friendly interface to identify each share. In this paper, we present a novel method to construct (k, n)-TaVCS. It can adjust visual quality of both the reconstructed secret image and the recovered tag image flexibly. Meanwhile, the proposed method provides better visual quality of both the reconstructed secret image and the recovered tag image under certain condition. Experimental results and theoretical analysis demonstrate the effectiveness of the proposed method.

Protecting Documents Using Visual Cryptography

Abstract: Digital documents are produced in enormous amounts everywhere in the digital world. The confidentiality, authenticity and integrity of these documents increased dramatically recently in the insecure networked environments. In this paper, we design new methods based on the visual cryptography and steganography to protect multiple digitized documents from threats created by unauthorized people. Visual cryptography is a visual secret sharing scheme used widely and proved to be secure enough in different areas. The experimental results demonstrate the efficacy of these methods to protect sufficiently multiple digital documents.

A Novel Quality Assessment for Visual Secret Sharing

Abstract: There is a variety of visual data, such as pictures, text, military or medical records, biometric patterns, etc. that need to be protected for privacy reasons. Visual secrets are different from textual secrets, in that the information obtained by perceiving the visual data needs to be protected. Visual secret sharing (or visual cryptography) [1] proposed in 1994 is a practical solution to this. The secret information is encrypted by hiding it into random looking shares. The secret data is encrypted in such a way that the decryption becomes a physical operation that is performed without computer. How much of the secret information can be retrieved depends on the visual quality of the decryption result. However, there is no practical tool for visual quality evaluation currently. The common visual quality metrics such as contrast [2], blackness [3], PSNR [4] and SSIM [5] cannot represent the visual quality properly as we demonstrate in our work. A fair and uniform visual quality metric is needed urgently. We propose a novel approach for visual quality evaluation. It is straightforward to implement and applicable to various applications in visual cryptography.

A new robust video watermarking algorithm against cropping and rotating attacks

Abstract: In this paper we propose a new video watermarking algorithm based on block classification and visual cryptography to enhance the robustness and imperceptibility based on spatial domain. A method of selecting frames as host frames is proposed based on shot segmentation which avoid embedding watermark into all frames. The watermark signal is cropped into small watermarks according to number of host frames in each shot. A method of selecting of host coefficients is proposed based on block classification using edge detection in spatial domain. Owner's share is generated based on block classification and sub-watermark bits. The imperceptibility of the watermarked video is improved by this way. The experiment results show that the proposed scheme has a good performance in maintaining realtime performance and resisting frame averaging, frame reduction and geometric attacks.

A Scalable Data Hiding Scheme Using Hilbert Space Curve and Chaos

Abstract: Data hiding techniques using visual cryptography use images as data carriers in such a way that human visual system cannot perceive any modifications in the images. Extensive work has been done on data hiding using gray scale images during the last two decades. Embedding capacity, visual quality of the stego-image, security and the complexity of the embedding algorithm are four main criteria in evaluating the performance of a data hiding scheme. In the present paper, a data hiding scheme is proposed that performs well on two important aspects - data security and embedding capacity while maintaining the quality of the stego-image. The proposed algorithm employs Hilbert space curve and chaotic maps to find out secure data locations with enhanced data security. The method is scalable for large data size and is also computationally convenient. Numerical results demonstrate effectiveness of the proposed algorithm.