Showing papers on "Visual cryptography published in 2018"
TL;DR: A new threshold RG-based VSS scheme aiming at improving the visual quality of the previewed image is presented and can gain better visual quality in the reconstructed images as well as (k, n) threshold.
Abstract: Random grids (RG)-based visual secret sharing (VSS) scheme can easily avoid the pixel expansion problem as well as requires no codebook design. However, previous scheme still suffers from low visual quality. In this paper, a new threshold RG-based VSS scheme aiming at improving the visual quality of the previewed image is presented. Compared with previous schemes, our scheme can gain better visual quality in the reconstructed images as well as (k, n) threshold. In addition, the factor affecting the visual quality is analyzed and the differences between related approaches are discussed.
104 citations
TL;DR: Experimental results indicate that the proposed turtle shell (TS)-based VSS scheme provides excellent visual quality and is superior to state-of-the-art VSS schemes.
Abstract: Visual secret sharing (VSS), also called visual cryptography, allows a secret image to be divided into several shares and the secret image can only be recovered through the collaboration of the shares. Due to high security and low computational complexity, VSS has been widely used in secure communications. In this paper, we propose the first turtle shell (TS)-based VSS scheme that shares the secret information into two meaningful shares. Firstly, a TS reference matrix is established. Then, secret information is hidden in a cover image to construct two meaningful shares with the help of TS reference matrix. The hidden secret information can be extracted without distortion if both shares are gathered and the cover image can be correctly restored by solving the location conflict problem. Moreover, an invalid share can easily be detected by the proposed scheme. Experimental results indicate that the proposed scheme provides excellent visual quality and is superior to state-of-the-art VSS schemes.
57 citations
TL;DR: A novel TiOISS scheme based on PBVCS using exclusive OR operation is proposed, which does not need complex computation in revealing process, and it can be used in real-time application.
Abstract: Perfect black visual cryptography scheme (PBVCS) shares a binary secret image into n shadows. Stacking any $$k(k
48 citations
TL;DR: Three progressive secret image sharing schemes are proposed that has smaller image-shadow size and higher quality of recovered image than visual cryptography based PSIS schemes, and has much more efficient operations in sharing procedure and image reconstruction procedure than polynomial basedPSIS schemes.
Abstract: ( k , n ) progressive secret image sharing (PSIS) schemes were discussed frequently in recent years. A ( k , n ) PSIS scheme consists of sharing phase and reconstruction phase. During sharing phase, a secret image is encrypted into n image-shadows; while during reconstruction phase, k to n image-shadows can progressively recover the image; fewer than k image-shadows get no information on the image. Most previous PSIS schemes can be divided into two categories, polynomial based PSIS schemes and visual cryptography based PSIS schemes. Polynomial based schemes can recover high quality image with complicated cryptographic computations; visual cryptography based PSIS schemes can reconstruct image using human visual system without any cryptographic computation, however, the size of image shadow expands largely from the image and the recovered image is quality-distortion. The motivation of this work is to solving the problems in existing PSIS schemes. Thus, in this paper, we adopt three Boolean operations: bit-level XOR, C O V ( 1 , 7 , 3 ) from ( 7 , 4 ) Hamming code and C O V ( 2 , 8 , 4 ) from ( 8 , 4 ) shortened Hamming code to propose three ( k , n ) PSIS schemes. In our schemes, k to n image-shadows can decrypt randomly partial pixels on entire image, and reconstruct image progressively. Comparing with previous PSIS schemes, our schemes has smaller image-shadow size and higher quality of recovered image than visual cryptography based PSIS schemes. On the other hand, our schemes has much more efficient operations in sharing procedure and image reconstruction procedure than polynomial based PSIS schemes.
36 citations
TL;DR: Comparative results based on various aspects of visual cryptography prove the efficiancy of the proposed approach over existing state-of-the-art approaches.
29 citations
TL;DR: Wang et al. as discussed by the authors proposed a visual-cryptographic image hiding method based on visual cryptography and volume grating optics, where the secret image is converted to the encrypted visual keys (VKs) according to the normal VC algorithm.
Abstract: In this paper, we propose a visual-cryptographic image hiding method based on visual cryptography (VC) and volume grating optics. The secret image is converted to the encrypted visual keys (VKs) according to the normal VC algorithm. Then the VKs are further embellished to the QR-code-like appearance and hidden as the holographic optical elements (HOEs), which are fabricated by the holographic exposure of photopolymer. In the decryption process, the fabricated HOE-VKs are illuminated with the laser beam. The reconstructed VKs are overlaid to extract the hidden information directly in the optical facility, without additional computation. Optical experiments verify that the VKs in HOE mode improves the system with high security and good robustness on the random noise attack. Besides, the volume grating nature also enlarges the system bandwidth by using the multiplexing technique. The proposed method may provide a promising potential for the practical image hiding systems.
27 citations
TL;DR: A novel QR code with two-level information storage is designed to protect private messages and is both feasible and reasonably secure, further enriching the application fields and outperforming the previous schemes significantly.
Abstract: The Quick Response (QR) code is designed for information storage recognizable by machine vision. With the popularity of QR code applications, the security of QR codes becomes hot issues concerned by many scholars. In this paper, a novel QR code with two-level information storage is designed to protect private messages. In the meantime, the public level can be directly decoded by any standard QR reader. In contrast to other studies, the computational complexity of the proposed scheme is reduced by combining with the theory of visual cryptography scheme (VCS). In addition, an important characteristic of the QR code, error correction capability, is preserved in this paper, guaranteeing the robustness to QR code damage. Experimental results and analysis show that the proposed scheme is both feasible and reasonably secure, further enriching the application fields and outperforming the previous schemes significantly.
19 citations
TL;DR: Experiments show that in spite of having various credentials of participants, embedded in shares, the contrast of the decoded secret image remains 50 % without reducing the level of secrecy, and proposed approach can effectively localize the tampered region of the share.
Abstract: In traditional k-out-of-n visual cryptography (VC), a secret image is visually decoded only if a subset of k or more shares are stacked together else nothing will be revealed. Progressive visual cryptography (PVC) scheme differs from the traditional VC where clarity and contrast of the decoded secret image are increased progressively with the number of stacked shares. Shares are most sensible objects since they carry secret; hence, verifying the reliability and authenticity of all shares before decoding the secret image prevents a participant from intentionally or unintentionally providing invalid data. This paper proposes a novel verifiable progressive visual cryptography approach with additional embedding capacity in each share which is used for self-embedding authentication data, copyright information along with confidential payload. These embedded informations in a share can be retrieved and verified at the time of any conflict. Proposed approach also eliminates many unnecessary encryption constraints of VC like pixel expansion, noise-like shares, explicit requirement of codebook and restriction on number of participants. Experiments show that in spite of having various credentials of participants, embedded in shares, the contrast of the decoded secret image remains 50 % without reducing the level of secrecy. By experiments, it is also confirmed that proposed approach can effectively localize the tampered region of the share.
18 citations
TL;DR: This paper proposes a probabilistic sharing model for visual cryptography scheme (VCS) combining with QR codes and highlights that the scheme can be used to authenticate the security of QR codes from some uncertain sources.
Abstract: In the past few years, visual cryptography scheme (VCS) has aroused much research attention and developed rapidly because of its simple decryption. However, meaningless shares remain a continuing challenge of VCS to its practical applications. In this paper, we propose a ( $k$ , $n$ )-VCS combining with QR codes. To enlarge the allowable maximum size of secret image, a probabilistic sharing model is utilized. Based on it, a secret sharing method is presented with high relative difference. Furthermore, we embed the initial shares into cover QR codes by using encoding redundancy. After that, each share is meaningful and can be read by any standard QR code reader. Different from previous work, error correction capacities of the covers are perfectly preserved. We also highlight that our scheme can be used to authenticate the security of QR codes from some uncertain sources. Finally, experimental results and comparisons are provided to show the feasibility and advantages of the proposed scheme.
18 citations
TL;DR: This paper considers the partial secret image sharing (PSIS) issue as well as propose a PSIS scheme for (n, n) threshold based on image inpainting and linear congruence (LC).
18 citations
TL;DR: This paper considers the new participants increasing issue as well as proposing a participants increasing method only from the n original shadow images generated by previous existed (k, n) threshold random grids-based visual secret sharing (RGVSS).
Abstract: In (k, n) visual secret sharing (VSS), a secret image is generated into n shadow images printed onto transparencies and distributed to n associated participants. The secret image can be recovered by stacking any k or more shadow images and human visual system without cryptographic computation. The previous VSS schemes neglected participants increasing. However, in some applications, some new shadow images need to be generated because some new participants join the secret sharing. In this paper, we consider the new participants increasing issue as well as propose a participants increasing method only from the n original shadow images generated by previous existed (k, n) threshold random grids-based visual secret sharing (RGVSS). Without knowing the original generation algorithm and the original secret image, q new shadow images can be obtained from the original n shadow images without reprinting the original ones, as a result $$(k, n+q)$$
threshold RGVSS will be gained. Theoretical analysis and experiments are conducted to evaluate the security and efficiency of the proposed scheme.
TL;DR: A novel Multi Secret Sharing scheme with unexpanded as well as meaningful shares has been proposed to protect two secret images at a time and experiments confirm that all meaningful shares fulfill the contrast and security conditions.
Abstract: Traditional Visual Cryptography (VC) facilitates a technique to protect only one secret image using single set of shares. Recent researches enhance the capabilities of traditional VC by providing the feature of Multi Secret Sharing (MSS), where more than one secret image can be protected at a time. In MSS different secret images are revealed by the stacking of same set of shares at different angles. Most of the existing state of art researches on MSS have common problem of pixel expansion and random pattern of the shares. Due to pixel expansion, there is wastage of the storage space and transmission time, moreover random pattern of the shares increases the vulnerability for cryptanalysis. In this paper a novel Multi Secret Sharing scheme with unexpanded as well as meaningful shares has been proposed to protect two secret images at a time. In the proposed approach the recovery probability of black pixels of the secret images in the decoded images is always 1 while that of white pixels, it is 0.25. Therefore the contrast of the decoded images is obtained as 25 % which is same as in most of the earlier researches with pixel expansion & random shares. Experiments confirm that all meaningful shares fulfill the contrast and security conditions. Secret images can be easily decoded by only human visual system without any computation at receiver end.
TL;DR: This article focuses on the study of various visual cryptographic schemes and analyses the performance on the basis of various parameters such as, pixel expansion, type of shares generated, image format, number of secret images, encryption method, etc.
Abstract: A visual cryptography scheme (VCS) allows one to decrypt images without any knowledge of cryptography and computational efforts. VCS allows secret image sharing such that we can divide the original...
TL;DR: An (2, n, m) multi secret sharing scheme in which exactly n share are generated to encode m secret images in which perfect alignment of shares between shares is not required to obtain secret image.
Abstract: Multi secret sharing is used to hide more than one secret information. In this approach secret information is divided in many parts and distributed among participants. Secret information may be in form of images also. Initially, Visual Cryptography (VC) applied for single secret images. After encryption process of VC, encrypted meaningless images are generated known as shares. Nowadays, multiple secret images may be secured by VC also. However, multi secret sharing schemes provide security to multiple images. Obtaining multiple images by using minimum number of shares is really an existing problem. Existing algorithms are limited to fix number of secret images with minimum number of shares. In this paper, we proposed an (2, n, m) multi secret sharing scheme in which exactly n share are generated to encode m secret images. If set of shares taken from qualified set then secret images revealed on the other hand set of shares taken from forbidden set than no information revealed. Minimum two shares ar...
TL;DR: A visual encryption algorithm based on DNA microarrays is proposed, which successfully integrates the advantages of the algorithm in information security with the natural advantages of modern biotechnology.
Abstract: Visual cryptography is a cryptographic technique that allows visual information to be encrypted in such a way that the decryption can be performed by humans. The power of DNA molecule comes from its memory capacity and parallel processing. In this article, a visual encryption algorithm based on DNA microarrays is proposed, which successfully integrates the advantages of the algorithm in information security with the natural advantages of modern biotechnology. The algorithm converts plaintext into QR code and then uses the visual encryption scheme to encrypt the QR code image. It combines with DNA microarray technology to achieve information encryption and decryption. Security analysis shows that this algorithm has high security.
TL;DR: A general model approach of real-time data hiding and watermarking for image, video and audio communications is proposed and a new potential method is introduced called SMLSB (Sequential Multiple LSB) method, which gives an advantage of robustness, while it provides various modes of the method depending on the requirements.
Abstract: In this paper, a general model approach of real-time data hiding and watermarking for image, video and audio communications is proposed. The aim is the development of security robustness variations and data-rate (capacity) extensions of Steganography fast schemes for RT (real time) or NRT (near real time) image, video and audio media communication and data hiding, with no significant distortion of the medium. Additionally, this paper includes the proposal of specific case models such as Steganography of the total of Visual Cryptography schemes of black and white images. Influenced by our survey on Spatial Domain Steganography techniques such as Multiple LSB (Least Significant Bit) algorithm, Matrix Embedding and Parity Coding, a new potential method is introduced called in brief from now on SMLSB (Sequential Multiple LSB) method comparing other respective methods and algorithms researched, SMLSB is a different approach on real-time and non-real-time data hiding, which gives an advantage of robustness, while it provides various modes of the method depending on the requirements. Also the method can be used for the specific occasion of Visual Cryptography Ciphers’ Steganography.
TL;DR: This paper proposes a (k, n) multi-factor cheating prevention visual cryptographic scheme (MCPVCS) with the large size of verification image, which can more easily authenticate the unambiguity of verify image.
TL;DR: Optimal secure visual cryptography for brain MRI medical image is proposed in this paper and visual cryptographic design is used for the purpose of image authentication and verification.
Abstract: Optimal secure visual cryptography for brain MRI medical image is proposed in this paper. Initially, the brain MRI images are selected and then discrete wavelet transform is applied to the brain MRI image for partitioning the image into blocks. Then Gaussian based cuckoo search algorithm is utilized to select the optimal position for every block. Next the proposed technique creates the dual shares from the secret image. Then the secret shares are embedded in the corresponding positions of the blocks. After embedding, the extraction operation is carried out. Here visual cryptographic design is used for the purpose of image authentication and verification. The extracted secret image has dual shares, based on that the receiver views the input image. The authentication and verification of medical image are assisted with the help of target database. All the secret images are registered previously in the target database. The performance of the proposed method is estimated by Peak Signal to Noise Ratio (PSNR), Mean square error (MSE) and normalized correlation. The implementation is done by MATLAB platform.
01 Jan 2018
TL;DR: This research work can give a way for providing authentication to all online Services by generating QR-code using zxing library that will converted into the three shares using Binary Visual cryptography algorithm.
Abstract: The startling improvement about web need aggravated the transmission, conveyance Also right to advanced networking really useful. Therefore, networking makers need aid more usually managing illegal What’s more unapproved utilization from claiming their productions. In our proposed approach, first enter the user name and password then generate QR-code using zxing library that will converted into the three shares using Binary Visual cryptography algorithm. Now share-4 is save in the database that is for future reference at receiver side. Remaining share-1, share-2 and share-3 are embedding into the Red, Green and Blue-component LL bit using of block DWT-SVD and Pseudo Zernike moment. After embedding add RGB Component. Now Color watermark image transfer from the network. As in network there are different attackers apply combination of Rotation, Scale and Translation attacks on the color watermark image. For recover the attacks first apply Pseudo Zernike moment, Surf feature on R, G and B-component they will extract the attacks pixel and recover the scale-angle using affine transformation. Now share-1, share-2, share-3 and another share-4 is in data base so we will apply EX-OR operation to get the QR-code. The final QR-code is decoded and we get the user name and password. This research work can give a way for providing authentication to all online Services.
TL;DR: A new Verifiable Multi-toned Visual Cryptography (VMVC) scheme is proposed to securely transmit the confidential images on web and provides cheating prevention, since each pixel of shares contains a self embedding verifiable bit for integrity test of that pixel.
Abstract: Traditional k out of n threshold visual cryptography scheme is proposed to hide a secret image into n shares, where only k or more shares can visually reveal the secret image. Most of the previous state of art approaches on visual cryptography are almost restricted in processing of binary images as secret, which are inadequate for many applications like securely transmission of medical images(Store and Forward Telemedicine), forensic images etc. In this paper, a new Verifiable Multi-toned Visual Cryptography (VMVC) scheme is proposed to securely transmit the confidential images on web. Proposed approach also provides cheating prevention, since each pixel of shares contains a self embedding verifiable bit for integrity test of that pixel. Many existing approaches are suffering from many unnecessary encryption constraints like random shares, codebook requirement, contrast loss etc, which all are successfully addressed in proposed approach. Some comparisons with previously proposed methods are also made. Experimental results and analysis are used to prove the efficiency of proposed approach.
TL;DR: A new RG-based threshold VSS with improved visual quality and lossless recovery ability is proposed, and the random bits are utilized to improve the visual quality as well as to decrease the darkness of the reconstructed secret image.
Abstract: Visual secret sharing (VSS) by random grids (RG) has gained much attention since it avoids the pixel expansion problem as well as requires no basic matrixes design. However, most of the previous RG-based threshold VSS still suffer from low visual quality or worse reconstructed secrets when more shadows are stacked. In this paper, a new RG-based threshold VSS with improved visual quality and lossless recovery ability is proposed. The random bits are utilized to improve the visual quality as well as to decrease the darkness of the reconstructed secret image. And the secret image can be losslessly recovered in the proposed scheme if the computational device is available. Simulation results and analyzes show the effectiveness of the proposed scheme. In addition, this paper gave the preliminary definition and evaluation of progressive secret sharing (PSS) based on mathematical differential and expectations.
TL;DR: Experimental results show that both methods can achieve excellent image visual quality and decoded visual patterns.
Abstract: In this paper, two methods are proposed to embed visual watermark into direct binary search (DBS) halftone images, which are called Adjusted Direct Binary Search (ADBS) and Dual Adjusted Direct Binary Search (DADBS). DADBS is an improved version of ADBS. By using the proposed methods, the visual watermark will be embedded into two halftone images separately, thus, the watermark can be revealed when these two halftone images are overlaid. Experimental results show that both methods can achieve excellent image visual quality and decoded visual patterns.
TL;DR: An optimized HVC scheme (OHVCS) using Error Diffusion (ED) is proposed in this paper, which eliminates the explicit requirement of codebook and reduces the random patterns of the shared images, as it encodes only the black pixels of the secret image, taking into account that the pixel expansion is the smallest size to be used.
Abstract: Halftone Visual Cryptography (HVC) is an encryption technique that encodes the secret image into halftone images in order to produce secure meaningful shares. Many methods have been proposed for developing HVC to protect the security of the images. Yet, these methods still have some problems such as poor visual quality of shares, large pixel expansion, interference of secret image on shared images, and interference shared images on retrieved image. To solve such problems, an optimized HVC scheme (OHVCS) using Error Diffusion (ED) is proposed in this paper. The proposed scheme eliminates the explicit requirement of codebook and reduces the random patterns of the shared images, as it encodes only the black pixels of the secret image, taking into account that the pixel expansion is the smallest size to be used. Moreover, it performs the basic concept of Visual Cryptography (VC); therefore, the security of the construction scheme is assured. The experimental results, performance evaluation through statistical analysis, and comparison with some existing schemes in various aspects of HVC show the effectiveness of the proposed scheme.
TL;DR: The (k, n) threshold image secret sharing technology can recover the secret image even n − k shares are lost, or n−k servers do not work, which is useful for cloud storage, etc.
Abstract: This article describes how the k, n threshold image secret sharing technology can recover the secret image even n-k shares are lost, or n-k servers do not work, which is useful for cloud storage, e...
TL;DR: The proposed model provides a secure mean to transmit or store highly classified data that could be applied to the public security sector and was examined by launching statistical and 8-bit plane visual attacks.
Abstract: Data security is required when communications over untrusted networks takes place. Security tools such as cryptography and steganography are applied to achieve such objectives, but both have limitations and susceptible to attacks if they were used individually. To overcome these limitations, we proposed a powerful and secured system based on the integration of cryptography and steganography. The secret message is encrypted with blowfish cipher and visual cryptography. Finally, the encrypted data is embedded into two innocent cover images for future transmission. An extended analysis was made to prove the efficiency of the proposed model by measuring Mean-Square-Error (MSE), Peak-Signal-to-noise-Ratio (PSNR), and image histogram. The robustness was examined by launching statistical and 8-bit plane visual attacks. The proposed model provides a secure mean to transmit or store highly classified data that could be applied to the public security sector.
TL;DR: A new construction of VCRG for general access structures is put forward, based on new insight into linear algebraic technique to construct VCS, where it is able to Construct VCS by solving a linear system of more equations at a time.
Abstract: Two visual models of image secret sharing have been studied: visual cryptography schemes (VCS), introduced by Naor and Shamir, and visual cryptograms of random grids (VCRG), introduced by Kafri and Keren. VCRG has gained much attention in academia than before to avoid the pixel expansion of VCS. Although there is a strict relation between VCRG and VCS, VCRG can still be improved to achieve a better result. In this paper, based on new insight into linear algebraic technique to construct VCS, where we are able to construct VCS by solving a linear system of more equations at a time, we put forward a new construction of VCRG for general access structures. The effectiveness and advantage of the proposed construction are formally analyzed and experimentally demonstrated. With theoretical and practical interests, our construction exposes new possibilities to the researches of visual models of image secret sharing.
01 Jan 2018
TL;DR: The result shows that the proposed technique is far better in terms of security but with some overheads when compared to stand-alone technique DCT.
Abstract: To provide security in communication networks, various cryptographic and steganographic algorithms have been proposed. Cryptography converts the data into a form understood only by the receiver node whereas steganography hides the data behind a cover file; generally, an image file is used. To provide better security, the use of hybrid mechanisms has been proposed. In this paper, we try to combine visual cryptography coupled with DCT to provide better security for communication networks. The proposed technique is implemented in MATLAB-12, and the overheads of mixing the two mechanisms are evaluated using several performance metrics such as PSNR, Mean Square Error (MSE), time complexity and Mean Absolute Error (MAE) of the mechanism. The result shows that the proposed technique is far better in terms of security but with some overheads when compared to stand-alone technique DCT.
29 Mar 2018
TL;DR: The aim of this survey paper is to provide the readers a layout of the first visual cryptography method, along with the various methods developed and proposed from time to time.
Abstract: Visual cryptography(VC) is a cryptographic methodology which permits visual information, for instance, text, pictures, etcetera to be encrypted such that the decryption can be performed by the human visual framework, without the assistance of PCs. The aim of this survey paper is to provide the readers a layout of the first visual cryptography method, along with the various methods developed and proposed from time to time. This paper also gives a survey of the applications that are based upon the concept of Visual Cryptography.
TL;DR: This paper combines PISSS and random grids-based VSS to remove all the drawbacks existing in the previous works including 1) distortion by compressing a secret image, 2) non-perfect reconstructed image, 3) distortion of pixel expansion, and 4) size-reduced halftone image.
Abstract: In an image secret sharing scheme (ISSS), two main categories are discussed. One is the polynomial-style image secret sharing scheme (PISSS), and the other is the visual secret sharing (VSS). It is interesting to combine the main properties of these two schemes. When the encoded secret images are received, we can decode them by combining these two schemes’ properties, utilizing the VSS property to seek the secret immediately by human visual system (HVS) and the PISSS property to recover the secret perfectly with a decoding machine. This paper combines PISSS and random grids-based VSS to remove all the drawbacks existing in the previous works including 1) distortion by compressing a secret image, 2) non-perfect reconstructed image, 3) distortion of pixel expansion, and 4) size-reduced halftone image. The experimental results demonstrate the proposed scheme does work well.
TL;DR: This paper builds a normal form hyper star access structure VCS from a full threshold VCS, and proves that its pixel expansion is optimal, and proposes a method of constructing general access structureVCS from its several decomposed normal formhyper star accessructure VCSs.