Showing papers on "Visual cryptography published in 2017"
31 Mar 2017
TL;DR: This volume gives academicians, researchers, and professionals the insight of well-known experts on key concepts, issues, trends, and technologies in this emerging field of secure image sharing.
Abstract: With rapid progress in Internet and digital imaging technology, there are more and more ways to easily create, publish, and distribute images. Considered the first book to focus on the relationship between digital imaging and privacy protection, Visual Cryptography and Secret Image Sharing is a complete introduction to novel security methods and sharing-control mechanisms used to protect against unauthorized data access and secure dissemination of sensitive information. Image data protection and image-based authentication techniques offer efficient solutions for controlling how private data and images are made available only to select people. Essential to the design of systems used to manage images that contain sensitive datasuch as medical records, financial transactions, and electronic voting systemsthe methods presented in this book are useful to counter traditional encryption techniques, which do not scale well and are less efficient when applied directly to image files. An exploration of the most prominent topics in digital imaging security, this book discusses: Potential for sharing multiple secrets Visual cryptography schemesbased either on the probabilistic reconstruction of the secret image, or on different logical operations for combining shared images Inclusion of pictures in the distributed shares Contrast enhancement techniques Color-image visual cryptography Cheating prevention Alignment problems for image shares Steganography and authentication In the continually evolving world of secure image sharing, a growing number of people are becoming involved as new applications and business models are being developed all the time. This contributed volume gives academicians, researchers, and professionals the insight of well-known experts on key concepts, issues, trends, and technologies in this emerging field.
86 citations
TL;DR: The test outcomes have revealed the fact that the peak signal to noise ratio is 58.0025, Mean square error value is 0.1164 and the correlation coefficient is 1 for the decrypted image without any sort of distortion of the original image.
Abstract: In visual cryptography, many shares are generated which are illogical containing certain message within themselves. When all shares are piled jointly, they tend to expose the secret of the image. The notion of visual secret sharing scheme is to encrypt a secret image into n illogical share images. It is unable to reveal any data on the original image if at least one of the shares is not achieved. The original image, in fact, is realized by overlapping the entire shares directly, in order that the human visual system is competent to identify the collective secret image without employing any complicated computational tools. Therefore, they are communicated steadily as number of shares. The elliptic curve cryptography approach, in turn, is employed to augment the privacy and safety of the image. The new-fangled technique is utilized to generate the multiple shares which are subjected to encryption and decryption by means of the elliptic curve cryptography technique. The test outcomes have revealed the fact that the peak signal to noise ratio is 58.0025, Mean square error value is 0.1164 and the correlation coefficient is 1 for the decrypted image without any sort of distortion of the original image.
65 citations
TL;DR: This paper puts forward constructions of perfect contrast XVCS using the linear algebraic technique without any assumptions such as participants may carry multiple shares or prior information about the shares are to be submitted during the secret reconstruction phase.
Abstract: XOR-based visual cryptography scheme (XVCS) was proposed to solve the poor visual quality problem without darkening the background in the reconstructed secret image. However, investigations on XVCS are not sufficient. In this paper, we focus on the traditional model of VCS for general access structures and exploit some extended capabilities for XVCS. Our main contributions are: (1) we put forward constructions of perfect contrast XVCS using the linear algebraic technique without any assumptions such as participants may carry multiple shares or prior information about the shares are to be submitted during the secret reconstruction phase; (2) for some restricted access structures, we achieve perfect contrast and perfect pixel expansion, namely both 1, which is impossible for any OR-based visual cryptography scheme (OVCS); (3) for general access structures, we achieve perfect contrast with smaller pixel expansion compared with many of the results in the literature; (4) Theoretical analysis on the proposed constructions are provided, as well as extensive experimental results and comparisons for demonstrating the effectiveness and advantages of our constructions.
45 citations
TL;DR: This paper is concerned with developing a biometric security solution for face images, using visual cryptography and zero-watermarking, that does not adversely impact the visual quality of the image.
Abstract: Fog and mobile edge computing have gained considerable attention from the research and development community. The problems related to security and privacy of biometric content are simpler to solve through edge computing resulting in improved security and privacy of biometric and other critically private information. Zero-watermarking has been proposed as a solution to help protect the ownership of multimedia content that is easy to copy and distribute. Visual cryptography is another approach to secure data that is to be shared through generating multiple shares. This paper is concerned with developing a biometric security solution for face images, using visual cryptography and zero-watermarking, that does not adversely impact the visual quality of the image. The original face image is not modified through the zero-watermarking and visual encryption procedures and this in turn does not adversely impact the recognition rate.
43 citations
TL;DR: A novel mechanism based on visual cryptography scheme (VCS) and aesthetic QR code is proposed, which contains three primary schemes for different concealment levels, which demonstrates the feasibility and security of the mobile payment authentication, the significant improvement of the concealment for the shadows in QR code, and the diversity of mobilepayment authentication.
Abstract: QR code (quick response code) is used due to its beneficial properties, especially in the mobile payment field. However, there exists an inevitable risk in the transaction process. It is not easily perceived that the attacker tampers with or replaces the QR code that contains merchant’s beneficiary account. Thus, it is of great urgency to conduct authentication of QR code. In this study, we propose a novel mechanism based on visual cryptography scheme (VCS) and aesthetic QR code, which contains three primary schemes for different concealment levels. The main steps of these schemes are as follows. Firstly, one original QR code is split into two shadows using VC multiple rules; secondly, the two shadows are embedded into the same background image, respectively, and the embedded results are fused with the same carrier QR code, respectively, using XOR mechanism of RS and QR code error correction mechanism. Finally, the two aesthetic QR codes can be stacked precisely and the original QR code is restored according to the defined VCS. Experiments corresponding to three proposed schemes are conducted and demonstrate the feasibility and security of the mobile payment authentication, the significant improvement of the concealment for the shadows in QR code, and the diversity of mobile payment authentication.
36 citations
TL;DR: The proposed HVCS inherits the good features of traditional VCS, such as, loss-tolerant e.g., k, n threshold and simply reconstructed method, and can support signal processing in the encrypted domain SPED.
Abstract: In this paper, homomorphic visual cryptographic scheme HVCS is proposed. The proposed HVCS inherits the good features of traditional VCS, such as, loss-tolerant e.g., k, n threshold and simply reconstructed method, where simply reconstructed method means that the decryption of the secret image is based on human visual system HVS without any cryptographic computation. In addition, the proposed HVCS can support signal processing in the encrypted domain SPED, e.g., homomorphic operations and authentication, which can protect the user's privacy as well as improve the security in some applications, such as, cloud computing and so on. Both the theoretical analysis and simulation results demonstrate the effectiveness and security of the proposed HVCS.
31 citations
TL;DR: A random-grid-based progressive visual secret sharing scheme, wherein the priority weighting of each share can be adjusted, wherein each share generated by the proposed scheme has a differentpriority weighting value.
28 citations
TL;DR: Two extended visual cryptography techniques for sharing color images are proposed that are lossless in nature and are less complex and have been shown to be effective by comparing their results with the results of the existing techniques on the basis of various parameters.
27 citations
TL;DR: Optical experiments verify that the high security, the easy extraction and the strong robustness are all obtainable in the visual-cryptography-based optical hiding.
Abstract: We propose an optical hiding method based on visual cryptography. In the hiding process, we convert the secret information into a set of fabricated phase-keys, which are completely independent of each other, intensity-detected-proof and image-covered, leading to the high security. During the extraction process, the covered phase-keys are illuminated with laser beams and then incoherently superimposed to extract the hidden information directly by human vision, without complicated optical implementations and any additional computation, resulting in the convenience of extraction. Also, the phase-keys are manufactured as the diffractive optical elements that are robust to the attacks, such as the blocking and the phase-noise. Optical experiments verify that the high security, the easy extraction and the strong robustness are all obtainable in the visual-cryptography-based optical hiding.
24 citations
TL;DR: Experimental results reveal that the proposed XOR-based progressive visual secret sharing scheme is superior to existing approaches with respect to performance and practicability.
24 citations
TL;DR: A novel method is proposed, which first makes use of Latin square to prevent cheating in VC, and is applicable to both ( k, n )-deterministic visual cryptography scheme (( k , n)-DVCS) and ( k,n )-probabilistic visual cryptography Scheme (PVCS).
Abstract: In the past decade, the researchers paid more attention to the cheating problem in visual cryptography (VC) so that many cheating prevention visual cryptography schemes (CPVCS) have been proposed. In this paper, the authors propose a novel method, which first makes use of Latin square to prevent cheating in VC. Latin squares are utilised to guide the choosing of authentication regions in different rows and columns of each divided block of the shares, which ensures that the choosing of authentication regions is both random and uniform. Without pixel expansion, the new method provides random regions authentication in each divided block of all shares. What is important is that the proposed method is applicable to both (
k
, n
)-deterministic visual cryptography scheme ((
k
, n
)-DVCS) and (
k
, n
)-probabilistic visual cryptography scheme ((
k
, n
)-PVCS). Experimental results and properties analysis are given to show the effectiveness of the proposed method.
TL;DR: The results clearly indicate that the proposed scheme can send more data with less bandwidth more secretly as well as provide more security to the image information.
Abstract: Security has gained a lot of importance with the rapid de velopment of communication/storage technology. Protecting the data has become an important issue. To provide more security to the image information, in this paper an enhanced security system has been proposed. Here the secret image is encrypted and transmitted by using a combined technique that make use of Discrete Wavelet Transform (DWT), Visual Cryptography (VC) and Water marking. DWT is first used for the compression of the secret image. The compressed image is used for further visual cryptographic process. VC encodes visual information into noise like shadow images called shares. By stacking the shares together the secret image can be visually decoded. Digital watermarking is used to provide additional security for the secret image. The generated shares are made invisible by using watermarking which also provides authentication for the shares. Different image types are used to evaluate the performance of the proposed scheme. Comparison with different values of scaling parameter M which is used to decrease the size of image in the VC is also done. The results clearly indicate that the proposed scheme can send more data with less bandwidth more secretly. RÉSUMÉ. La sécurité a pris beaucoup d'importance avec le développement rapide de la technologie de communication / stockage. La protection des données est devenue un enjeu important. Pour renforcer la sécurité des informations sur les images, un système de sécurité amélioré a été proposé dans cet article. Ici, l’image secrète est cryptée et transmise à l’aide d’une technique combinée utilisant la transformation en ondelettes discrète (DWT), la cryptographie visuelle (VC) et le filigrane. DWT est d'abord utilisé pour la compression de l'image secrète. L'image compressée est utilisée pour un processus cryptographique visuel ultérieur. VC code des informations visuelles en bruit, telles que des images d’ombre appelées des partages. En empilant les partages ensemble, l'image secrète peut être décodée visuellement. Le filigrane numérique est utilisé pour renforcer la sécurité de l'image secrète. Les partages générés sont rendus invisibles à l'aide d'un filigrane qui fournit également une authentification pour les partages. Différents types d’images sont utilisés pour évaluer les performances du schéma proposé. Une comparaison avec différentes valeurs du paramètre de mise à l'échelle M utilisé pour réduire la taille de l'image dans le VC est également effectuée. Les résultats indiquent clairement que le schéma proposé peut envoyer plus de données avec moins de bande passante de manière plus secrète.
TL;DR: An enhanced form of the proposed method based on the concept of visual cryptography for color images and without any pixel expansion which requires less space is produced by modifying the encryption technique used to generate the random and the key shares.
Abstract: Visual cryptography (VC) is one of the best techniques used to secure information. It uses the human vision to decrypt the encrypted images without any cryptographic computations. The basic concept of visual cryptography is splitting the secret image into shares such that when the shares are stacked, the secret image is revealed. In this paper we proposed a method that is based on the concept of visual cryptography for color images and without any pixel expansion which requires less space. The proposed method is used to encrypt halftone color images by generating two shares, random and key shares which are the same size as the secret color image. The two shares are generated based on a private key. At the receiving side, the secret color image is revealed by stacking the two shares and exploiting the human vision system. In this paper, we produce an enhanced form of the proposed method by modifying the encryption technique used to generate the random and the key shares. Experimental results have shown that the proposed and the enhanced methods suggest an efficient way to encrypt a secret color image with better level of security, less storage space, less time of computation and with a better value of PSNR.
TL;DR: A progressive VSS (PVSS) algorithm for GAS with improved visual quality based on RG that has neither pixel expansion nor codebook design due to RG is developed.
TL;DR: This contribution is the first one to integrate visual features and cryptographic features of VC shares into Hash code for the purpose of VC authentication.
Abstract: Visual Cryptography (VC) has been developed as a significant research arena in media security. Despite of its obvious strengths, recent investigations have debated this scheme from adverse aspects, its problem is lack of authentication of VC shares, VC authentication related to digital image processing and cryptography has not been fully integrated together in the past years. In this paper, we analyze both visual features and cryptographic features of VC shares and take use of them for VC authentication. Compared to those existing methods, our contribution is the first one to integrate visual features and cryptographic features of VC shares into Hash code for the purpose of VC authentication.
TL;DR: A Modified TiOISSS is proposed in which an adaptive threshold is used for halftoning, which changes depending on the nature of the pixels present in image, which shows that the quality of reconstructed secret image is improved in the first decoding stage compared to the existing scheme.
Abstract: Visual Cryptography Scheme (VCS) is a cryptographic technique which can hide image based secrets. Even though VCS has the major advantage that the decoding can be done with the help of Human Visual System (HVS), yet it does not provide sufficient reconstruction quality. Hence, Two in One Image Secret Sharing Scheme (TiOISSS) is used which provides two decoding phases. However, the existing TiOISSS method has several limitations. In this work, a Modified TiOISSS is proposed in which an adaptive threshold is used for halftoning, which changes depending on the nature of the pixels present in image. By this, the quality of reconstructed secret image is improved in the first decoding stage compared to the existing scheme. In addition, the security is also enhanced by pixel and bit level permutation with a 64 bit key and embedding the key in Gray VCS shadows. To verify the authenticity of the image, a secret message is also embedded in the shadows. Security analysis shows that the Modified TiOISSS is robust to Brute Force and Man-in-Middle attacks.
TL;DR: Sufficient theoretical analysis and extensive experimental results are provided in this paper, showing the effectiveness and advantages of the proposed RAVCS method for sharing a binary secret image into multiple absolute moment block truncation coding shadows.
01 Feb 2017
TL;DR: Analysis of different algorithms performed which generates meaningful shares are performed and combination of Digital watermarking and visual cryptography adds enhanced security to secret images.
Abstract: In today's world of digital communication, as technology progresses, there is more and more attention required on image security. Many visual cryptography algorithms have been suggested and digital watermarking in association with visual cryptography is also proposed for more image security. An image watermarking model based on progressive visual cryptography is proposed to decide optimal number of shares. A study on implementation of meaningful shares in combination with visual cryptography scheme for secret images is carried out for implementation of algorithm. A visual cryptography techniques are used to create meaningful shares. In this paper analysis of different algorithms are performed which generates meaningful shares. These shares are watermarked with cover images. After transmission of these watermarked images to receiving end, the receiving end will extract the shares from watermarked images and stacking of these extracted meaningful shares will generate the original secret image. Combination of Digital watermarking and visual cryptography adds enhanced security to secret images.
TL;DR: Visual cryptography is an emerging technology to address the concerns regarding privacy of images and is a powerful technique combining both the impeccable ciphers and secret sharing in cryptography with that of the raster graphics.
Abstract: Visual cryptography is an emerging technology to address the concerns regarding privacy of images. It is a powerful technique combining both the impeccable ciphers and secret sharing in cryptograph...
TL;DR: This paper proposes a VSS scheme with multi-level encoding based on a generalized random grid, which can retrieve the secret in a multi- level secret image with a high visual quality using the XOR operant during decryption.
Abstract: Most visual secret sharing (VSS) schemes are employed for the secret sharing of binary secret images. In these schemes, the share appears as a noise-like image, such that no information about the secret image can be obtained from an individual share. The recovered secret message can only be decrypted by the human eye following rendering using two different light transmissions. However, these schemes do not apply well to gray-level secret images because the halftone region of gray-level secret images cannot be adequately recovered. In this paper, we propose a VSS scheme with multi-level encoding based on a generalized random grid, which can retrieve the secret in a multi-level secret image with a high visual quality using the XOR operant during decryption. The proposed method produces a share of the same size as the original secret image without pixel expansion and does not require a codebook in the encoding process.
01 Sep 2017
TL;DR: A survey has been done on various visual cryptography schemes based on the number of secret, pixel expansion, type of share generated, image format, and number ofsecret image.
Abstract: Visual cryptography is a powerful technique in which a secret image can be divided into two or more shares and the decryption can be done using human visual system Visual cryptography has wide range of applications like in biometrics, print online banking, cloud computing, internet voting, etc The basic method of visual cryptography is a secret image is hidden into two or more shares which on superimposing will recover the hidden image During the recovery it is not possible to get the original image due to various reasons like pixel expansion, contrast, storage, security, image types Therefore various techniques have been developed to address these issues A survey has been done on various visual cryptography schemes based on the number of secret, pixel expansion, type of share generated, image format, and number of secret image
01 Feb 2017
TL;DR: The proposed method can be used as a cryptographic algorithm and also for secret sharing as well as visual secret sharing, and two variant of a secret sharing scheme using Gray code and XOR operation are proposed.
Abstract: Secret sharing refers to method for distributing a secret among a group of participants. It is also known as secret splitting. In this, each of the participants is allocated a share of the secret. The individual share doesn't carry any information. The secret can be reconstructed only when a sufficient number or all of shares are combined together. Secret-sharing schemes are important tools in cryptography and they are used as building blocks in many secure protocols, e.g., general protocol for multiparty computation, Byzantine agreement, threshold cryptography, access control, attribute-based encryption, and generalized oblivious transfer. Visual secret sharing, aka Visual Cryptography, provides a very powerful technique by which visual secret can be distributed into two or more shares. When the shares are combined together, the original visual secret can be discovered. In this paper, as first part, many types of secret sharing schemes are examined. Secondly we proposed two variant of a secret sharing scheme using Gray code and XOR operation. The Gray code is used to construct the shares and the XOR operation is used to reconstruct the secret. The proposed method can be used as a cryptographic algorithm and also for secret sharing as well as visual secret sharing.
TL;DR: A robust and blind watermarking scheme based on visual cryptography for copyright protection of digital images that can resist several attacks such as JPEG compression, gamma correction, impulse noise, Gaussian noise, blurring, median filter, rotation, scaling, and sharpening attacks on different types of images.
Abstract: The paper proposes a robust and blind watermarking scheme based on visual cryptography for copyright protection of digital images. It shuffles the pixel locations of the binary watermark using Arnold cat map transform to realize the effect of encryption for better security and it divides the image into blocks of equal size. Two secret shares are generated from the watermark and the image based on visual cryptography by comparing the global mean value of the pixels in the image with the mean values of all pixels of randomly selected blocks. As documented in the experimental results, the proposed scheme is more robust in comparison with other visual cryptography-based watermarking schemes. It can resist several attacks such as JPEG compression, gamma correction, impulse noise, Gaussian noise, blurring, median filter, rotation, scaling, and sharpening attacks on different types of images. The computational time for generating secret shares and detection of the watermark is comparatively small.
30 Mar 2017
TL;DR: The analysis, design and implementation phase of the software development of the voting system is discussed in detail and techniques like the password hashed based scheme, visual cryptography, F5 image steganography and threshold decryption cryptosystem are incorporated.
Abstract: This paper discusses the implementation of an online voting system based on image steganography and visual cryptography. The system was implemented in Java EE on a web-based interface, with MySQL database server and Glassfish application server as the backend. After considering the requirements of an online voting system, current technologies on electronic voting schemes in published literature were examined. Next, the cryptographic and steganography techniques best suited for the requirements of the voting system were chosen, and the software was implemented. We have incorporated in our system techniques like the password hashed based scheme, visual cryptography, F5 image steganography and threshold decryption cryptosystem. The analysis, design and implementation phase of the software development of the voting system is discussed in detail. We have also used a questionnaire survey and did the user acceptance testing of the system.
TL;DR: The VCS is a variant form of secret sharing method to encode a secret image into n distinct shares that, while certain qualified subsets of participants can visually recover the secret, but other forbidden sets of participants have no information on the secret.
Abstract: Visual Cryptographic scheme (VCS) is a variant form of secret sharing method to encode a secret image into n distinct shares. The dealer distributes shares to each participants in such a way that, while certain qualified subsets of participants can visually recover the secret, but other forbidden sets of participants have no information on the secret. Such a system is the general access structures in VCS. The essential access structure (k, n)* is a type of threshold scheme were one participant is the leader who holds the essential share and the remaining n-1 shares are given to n-1 participants. The secret image cannot be retrieved in the absence of leader and the leader needs the support of at least k-1 remaining participants to recover the secret image. Small pixel expansion and maximum contrast are the basic parameters for measuring the quality of the VCS. In the literature there are constructions for both deterministic and probabilistic (k, n)*-VCS. The following are the important contribution...
TL;DR: A new XOR based Continuous-tone Multi Secret Sharing scheme suitable for store-and-forward telemedicine is proposed to securely transmit the medical images and preserves all basic characteristics of traditional VC but also increases the capacity of secret image sharing.
Abstract: Traditional k out of n visual cryptography scheme has been proposed to encrypt single secret image into n shares where only k or more shares can decode the secret image. Many existing schemes on visual cryptography are restricted to consider only binary images as secret which are not appropriate for many important applications. Store-and-Forward telemedicine is one such application where medical images are transmitted from one site to another via electronic medium to analyze the patient's clinical health status. The main objective of Store-and-Forward telemedicine is to provide remote clinical services via two-way communication between the patient and the healthcare provider using electronic medical image, audio and video means. In this paper, a new XOR based Continuous-tone Multi Secret Sharing scheme suitable for store-and-forward telemedicine is proposed to securely transmit the medical images. It also eliminates basic security constraints of VC like pixel expansion in shares/recovered secret images, random pattern of shares, explicit codebook requirement, lossy recovery of secret and limitation on number of secret and shares. Proposed approach is n out of n multi secret sharing scheme which is able to transmit n secret images simultaneously. All secrets could be revealed only after some computations with all n shares and one master share. Master share has been created with the secret key at encoding phase and it can be regenerated at the time of decoding using same secret key. Here all shares are meaningful in continuous-tone which may provide confidentiality to medical images during transmission. Proposed approach not only preserves all basic characteristics of traditional VC but also increases the capacity of secret image sharing. From the experiments we found that irrespective of visible contents of the shares, the probability of getting back the pixel values of respective original secret images at the receiver end is very high.
13 Apr 2017
TL;DR: This work suggests enhanced password processing scheme based on image using visual cryptography (VC), which has lower computation, prevents cyber-attack aimed at hash-cracking, and supports authentication not to expose personal information such as ID to attackers.
Abstract: Traditional password conversion scheme for user authentication is to transform the passwords into hash values. These hash-based password schemes are comparatively simple and fast because those are based on text and famed cryptography. However, those can be exposed to cyber-attacks utilizing password by cracking tool or hash-cracking online sites. Attackers can thoroughly figure out an original password from hash value when that is relatively simple and plain. As a result, many hacking accidents have been happened predominantly in systems adopting those hash-based schemes. In this work, we suggest enhanced password processing scheme based on image using visual cryptography (VC). Different from the traditional scheme based on hash and text, our scheme transforms a user ID of text type to two images encrypted by VC. The user should make two images consisted of subpixels by random function with SEED which includes personal information. The server only has user's ID and one of the images instead of password. When the user logs in and sends another image, the server can extract ID by utilizing OCR (Optical Character Recognition). As a result, it can authenticate user by comparing extracted ID with the saved one. Our proposal has lower computation, prevents cyber-attack aimed at hash-cracking, and supports authentication not to expose personal information such as ID to attackers.
23 Aug 2017
TL;DR: A new kind of VCS which is implemented on modern display terminal of high refresh rates and based on the proposed VCS, an information security display technology that can prevent unauthorized photography is implemented.
Abstract: Visual cryptography scheme (VCS) is an image secret sharing method which exploits the spatial responds characteristics of Human visual system (HVS). Applications of traditional OR and XOR based VCSs are seriously limited by the implementation carrier in practice. In this paper, we proposed a new kind of VCS which is implemented on modern display terminal of high refresh rates. Our approach exploits the temporal responds characteristics of HVS that light signals are temporal integrated into a single steady continuous one if the frequency exceeds critical fusion frequency (CFF). Furthermore, basing on the proposed VCS, we implement an information security display technology that can prevent unauthorized photography. Only authorized viewers can recover the secret information with the help of synchronized glass. While unauthorized viewers with naked eye or camera get nothing about the secret information. Experimental results show the effectiveness of proposed temporal integration based VCS and information security display technology.
01 Jul 2017
TL;DR: This work proposes visual cryptography encryption framework by using an algorithm developed by Floyd and Steinberg's for error diffusion for grayscale as well as color images to encrypt a secret picture (image) into different share images.
Abstract: Visual cryptographic schemes (VCS) allow one(at the sender side) to encrypt a secret picture (image) into different share images. Here no share image does uncovers any knowledge concerning to the original secret image. This work proposes visual cryptography encryption framework by using an algorithm developed by Floyd and Steinberg's for error diffusion for grayscale as well as color images. Floyd Steinberg diffusion technique continuously delivers(generates) delighting colored halftoned images for our natural vision system of humans. A color image to be protected is taken as input and then this image is decomposed into three separate monochromatic images based on CMY color space. The computer simulation demonstrates that the visual nature and tone (in terms of quality) of the acquired halftoned shares is acceptable.