Top PDF A New Visual Cryptography Scheme for Color Images

A New Visual Cryptography Scheme for Color Images

A New Visual Cryptography Scheme for Color Images

Visual cryptography is a method for protecting image-based secrets that has a computation-free decoding process. In this paper, we proposed a visual cryptographic system which can be used to hide the original image information from an intruder or an unwanted user. The images can be in any standard format. The encrypted image is sent to the destination through the network and then the image is decrypted. We used symmetric key cryptography. Experimental results indicate the proposed method is a simple, practical and effective cryptographic system.

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A VC-Based Copyright Protection Scheme for Digital Images of Multi-Authorship

A VC-Based Copyright Protection Scheme for Digital Images of Multi-Authorship

In 1994, a new cryptographic paradigm, called visual cryptography or visual secret sharing (VSS), was firstly introduced by Naor and Shamir [7]. It can encode a black-and-white secret image into n shares, which are printed on transparencies separately and distributed to n separate participants. Those who belong to a qualified set can see the secret image by stacking up their transparencies together. For example, in a k-out-of-n VSS scheme, the secret is visible only when at least k or more shares are stacked together. Hence VSS scheme is suitable for group secret sharing without the help of a computer. A VSS scheme is constructed for an access structure, (Γ Qual , Γ Forb ), which specifies how the secret is shared among
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INVOLUTORY MATRIX IN VISUAL CRYPTOGRAPHY

INVOLUTORY MATRIX IN VISUAL CRYPTOGRAPHY

Hill cipher can be adopted to encrypt grayscale and color images, For grayscale images, the modulus will be 256 (the number of levels is considered as the number of alphabets). In the case of color images, the color image is first decomposed into (R-G-B) components. Secondly, each component (R-G-B) is encrypted separately by the algorithm. Finally, the encrypted components are concatenated together to get the encrypted color image.

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State-of-the-Art Visual Cryptography Schemes

State-of-the-Art Visual Cryptography Schemes

There are a several techniques related to aspects of the Information Security such as confidentiality, data security, entity authentication and data origin authentication, One of these techniques Visual Cryptography, which is a new technique which provides information security which uses simple algorithm unlike the complex, computationally intensive algorithms used in other techniques in traditional cryptography. This technique allows Visual information (pictures, text, etc.) to be encrypted in such a way that their decryption can be performed by the human visual system, without any complex cryptographic algorithms. Visual cryptography was originally invented and introduced in 1994 by Noar and Shamir [1]. Visualcryptography is a cryptographic technique which allows visual information (e.g. printed text,handwritten notes and pictures) to be encrypted in such a way that the decryption can beperformed by the human visual system, without the aid of computers. Visual cryptographyScheme eliminates complex computation problem in decryption process, and the secretimages can be restored by stacking operation. This property makes visual cryptographyespecially useful for the low computation load requirement. In a t-out-of-n scheme of VC, a secret binary image (SI) is cryptographically encoded into n shares of random binary patterns. The n shares are Xeroxed onto n transparencies, respectively, and distributed amongst n participants, one for each participant. No participant knows the share given to another participant. Any t or more participants can visually reveal the secret image by superimposing any t transparencies together. The secret cannot be decoded by any t-1 or fewer participants, even if infinite computational power is available to them. Being a type of
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Automatic eye localization in color images

Automatic eye localization in color images

In general, eye localization methods consist on classifiers built using a combination of well-known approaches for pattern recognition and machine learning: neural networks, SVM, boosting, regression, Bayesian modeling, among others. We propose a new eye localization method that is based on a simpler approach and exploits visual clues present in color images. Multi-scale localization is naturally supported due to the geometric nature of the clustering algorithm used as part of the search.

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New Colors for Histology: Optimized Bivariate Color Maps Increase Perceptual Contrast in Histological Images.

New Colors for Histology: Optimized Bivariate Color Maps Increase Perceptual Contrast in Histological Images.

The diagnosis of many, especially of malignant, diseases, relies on the evaluation of histological sections by a pathologist. Also, in basic and translational research, interpretation of histological sections is the basis for scientific conclusions. Accuracy and efficiency of this visual diagnostic process is determined by a number of factors. Four of these factors are commonly considered: first, the original tissue sample must comply with certain standards, then, the fixation and staining procedures should be standardized and optimized [1–4]. Third, the optical properties of the diagnostic microscope or digital scanner, the characteristics of the image acquisition (e.g. CCD-chip) and data storage should be calibrated to achieve capture a maximum amount of information present in the sample [5, 6]. Lastly, for digital pathology, display calibration can have an effect on diagnostic efficacy [7]. However, there is an additional information bottle- neck in the diagnostic cascade of tissue samples: in order to be interpreted, the histological image information has to be processed by the visual system of the evaluating pathologist [8, 9]. Even if all sample preparation steps are fully optimized, it is conceivable that the resulting image is not optimally suited for the visual system of an observer and that therefore, a propor- tion of the available information is lost.
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A novel cryptographic technique under visual secret sharing scheme for binary images

A novel cryptographic technique under visual secret sharing scheme for binary images

This paper presented a new visual sharing scheme with (3, 6) and (4, 4) for visual cryptography. The proposed scheme reduced the no. of shares for more participants compared to equal shares and participants proposed earlier papers. As the no. of shares is reduced, system complexity is reduced. Decoding becomes easy with less no. of shares.

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Animal detection in natural images: effects of color and image database.

Animal detection in natural images: effects of color and image database.

The visual system has a remarkable ability to extract categorical information from complex natural scenes. In order to elucidate the role of low-level image features for the recognition of objects in natural scenes, we recorded saccadic eye movements and event-related potentials (ERPs) in two experiments, in which human subjects had to detect animals in previously unseen natural images. We used a new natural image database (ANID) that is free of some of the potential artifacts that have plagued the widely used COREL images. Color and grayscale images picked from the ANID and COREL databases were used. In all experiments, color images induced a greater N1 EEG component at earlier time points than grayscale images. We suggest that this influence of color in animal detection may be masked by later processes when measuring reation times. The ERP results of go/nogo and forced choice tasks were similar to those reported earlier. The non- animal stimuli induced bigger N1 than animal stimuli both in the COREL and ANID databases. This result indicates ultra-fast processing of animal images is possible irrespective of the particular database. With the ANID images, the difference between color and grayscale images is more pronounced than with the COREL images. The earlier use of the COREL images might have led to an underestimation of the contribution of color. Therefore, we conclude that the ANID image database is better suited for the investigation of the processing of natural scenes than other databases commonly used.
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IMPACT OF ERROR FILTERS ON SHARES IN HALFTONE VISUAL CRYPTOGRAPHY

IMPACT OF ERROR FILTERS ON SHARES IN HALFTONE VISUAL CRYPTOGRAPHY

Traditional VC constructions are exclusively based on combinational techniques. In the halftoning framework of VC, a secret binary image is encrypted into high quality halftone images, or halftone shares. In particular, this method applies the rich theory of blue noise halftoning to the construction mechanism used in conventional VSS schemes to generate halftone shares, while the security properties are still maintained, the decoded secret image has uniform contrast. The halftone shares carry significant visual information to the reviewers, such as landscapes, buildings, etc. the visual quality obtained by the new method is significantly better than that attained by any available VSS method known to date. As a result, adversaries, inspecting a halftone share, are less likely to suspect that cryptographic information is hidden. A higher security level is thus achieved [5]. Error diffusion algorithm [5] is used to achieve improved halftone image quality in each share.
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Design and Implementation of Hierarchical Visual Cryptography with Expansionless Shares

Design and Implementation of Hierarchical Visual Cryptography with Expansionless Shares

image must follow portable network graphics format. In binary documents there are only two possibilities of pixel values viz. black and white. Here authors used 0 to represent black information and 1 to represent white information [4]. Stegenography and visual cryptography concepts were combined by George Abboud to share the hidden message. The idea was quite novel but increased complexity during the computation of shares [5]. In 2008 the concept was proposed to use visual cryptography for banking applications. The authors stated that visual cryptography based signature authentication is more secured than password based authentication. Individual pixel value in the secret is indicated by f(x, y) before processing and by g(x, y) after processing. In any situations for binary secret the values of these two functions are either 0 or 1 [6]. In 2010, cheating prevention mechanism was stated using visual cryptography by Bin Yu [7]. In the same year Li Fang proposed that multiple secrets could be encrypted in the same pairs of shares [8]. Contrast enhancement in visual cryptography was proposed by Thomos Monoth efficiently increased the contrast level of revealed secret [9]. The motivation for Hierarchical visual cryptography oriented from visual cryptography and the need of secured authentication mechanism based on visual cryptography. In 2000, Yang C.n and Laih C.S stated color visual cryptography scheme. According to these authors color information like image is easily encrypted using color VC scheme. Time Complexity was the major issue of discuss in this paper [10]. A segment-based visual cryptography suggested by Borchert [11] can be used only to encrypt the messages containing symbols, especially numbers like bank account number, amount etc. [11]. In 2013, Omprasad and Sonavane developed visual
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Visual Digital Signature Scheme: A New Approach

Visual Digital Signature Scheme: A New Approach

Abstract —A digital signature is an important public-key primitive that performs the function of conventional handwritten signatures for entity authentication, data integrity, and non-repudiation, especially within the electronic commerce environment. Currently, most conventional digital signature schemes are based on mathematical hard problems. These mathematical algorithms require computers to perform the heavy and complex computations to generate and verify the keys and signatures. In 1995, Naor and Shamir proposed a visual cryptography (VC) for binary images. VC has high security and requires simple computations. The purpose of this paper is to provide an alternative to the current digital signature technology. In this paper, we introduce a new digital signature scheme based on the concept of a non-expansion visual cryptography. A visual digital signature scheme is a method to enable visual verification of the authenticity of an image in an insecure environment without the need to perform any complex computations. Our proposed scheme generates visual shares and manipulates them using the simple Boolean operations OR rather than generating and computing large and long random integer values as in the conventional digital signature schemes currently in use.
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DWT-SVD BASED SECURED IMAGE WATERMARKING FOR COPYRIGHT PROTECTION USING VISUAL CRYPTOGRAPHY

DWT-SVD BASED SECURED IMAGE WATERMARKING FOR COPYRIGHT PROTECTION USING VISUAL CRYPTOGRAPHY

Chang and Chuang [10] proposed a scheme based on torus automorphism and visual cryptography. Watermark is embedded without altering the host image. Lou, Shieh, and Tso [11] developed a copyright protection scheme based on chaos and VC techniques. The limitation of the scheme is that it does not provide the main characteristic of VC and uses the Human Visual System to decrypt secret messages. The watermark is retrieved by performing an XOR operation between the shadow images. In 2005 Hsu and Hou [12] proposed a copyright protection based on sampling distribution of means and Visual Cryptography to achieve the requirements of robustness and security. The secret message can be identified by the HVS directly without the aid of computers.
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Design and Implementation of a Novel Authentication Algorithm for Fool-Proof Lock-Key System Based On Visual Secret Sharing Scheme

Design and Implementation of a Novel Authentication Algorithm for Fool-Proof Lock-Key System Based On Visual Secret Sharing Scheme

In the scheme, one pixel of the original image is reproduced by m sub pixels on the sheets. The pixel is considered “on” (transparent) if the number of transparent sub pixels is more than a constant threshold, and “off”(opaque) if the transparent sub pixels is less than a constant lower threshold, when the sheets are stacked together. The contrast α is the difference between the on and off threshold number of transparent pixels. Ateniese et al. [18] has extended the (k, n) VSSS to general access structures where senders can specify all qualified and forbidden subsets of n participants. Droste et. al. [16] considered the problem of sharing more than one secret image among a set of participants, and proposed a method to reconstruct different images with different combinations of sheets. Hofmeister et. al. [17] has discussed to maximize the contrast α using linear programming in the cases of k {3, 4, n}. Visual cryptography is based on Boolean operations. Therefore half toning is necessary for applying visual cryptography to grayscale images. The proposed mechanism makes some consideration on the average transparency of a pixel in the context of half toning techniques.
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Multi-pixel Visual Cryptography for color images with Meaningful Shares

Multi-pixel Visual Cryptography for color images with Meaningful Shares

Different kernels of halftone (Figure 3.9) are compared. Stucki kernel gives better halftone visual quality. Shares before watermark are random dots so it does not reveal the secret information. For better security, shares are watermarked on other cover image using simple watermark algorithm. This gives meaningful shares without revealing the secret information. The secret information is revealed by overlapping of meaningful shares. The quality of recovered image (Figure 3.7) is improved by filters.

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New Steganographic Scheme Based Of Reed- Solomon Codes

New Steganographic Scheme Based Of Reed- Solomon Codes

The word detection is also used when it is about of checking the presence of information (represented thanks to a signal, a particular characteristic of the medium…) in the stego- medium, without to want to extract it Several techniques of Steganographic scheme have been proposed among which one can retain the technique “matrix embedding”.

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Acceptance / Rejection Rule Based Algorithm for Multiple Face Detection in Color Images

Acceptance / Rejection Rule Based Algorithm for Multiple Face Detection in Color Images

System overview of proposed algorithm is shown in figure 1. Images for experiments are taken from internet to check the reliability of system against large range of intensity variation in input image. Our algorithm gives the robust results for single face and multiple face images with different face size and with different face orientations. We have tested system for standard face database too (CVL face database is used for practice). As images are taken from the internet, size and intensity of the images are different. As a first step of processing, we are resizing the image with scale of 400 X 600 pixels resolution to reduce the processing time. We have carried out the entire experiment on the data set of 118 images which contains more than 1000 faces. Images are having differently scaled and oriented faces in it. Accuracy of our algorithm is more than 90 %.
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DIGITAL WATERMARKING SCHEMES FOR AUTHORIZATION AGAINST COPYING OR PIRACY OF COLOR IMAGES

DIGITAL WATERMARKING SCHEMES FOR AUTHORIZATION AGAINST COPYING OR PIRACY OF COLOR IMAGES

The Discrete Wavelet Transform (DWT)[8] is currently used in a wide variety of signal processing applications, such as in audio and video compression, removal of noise in audio, and the simulation of wireless antenna distribution. Wavelets have their energy concentrated in time and are well suited for the analysis of transient, time- varying signals. Since most of the real life signals encountered are time varying in nature, the Wavelet Transform suits many applications very well [6]. We use the DWT to implement a simple watermarking scheme. The 2-D discrete wavelet transforms (DWT) decomposes the image into sub-images, 3 details and 1 approximation. The approximation looks just like the original; only on 1/4 the scale. The 2-D DWT is an application of the 1-D DWT in both the horizontal and the vertical directions. The DWT separates an image into a lower resolution approximation image (LL) as well as horizontal (HL), vertical (LH) and diagonal (HH) detail components. The low-pass and high- pass filters of the wavelet transform naturally break a signal into similar (low pass) and discontinuous/rapidly- changing (high-pass) sub-signals. The slow changing aspects of a signal are preserved in the channel with the low- pass filter and the quickly changing parts are kept in the high-pass filter’s channel. Therefore we can embed high- energy watermarks in the regions that human vision is less sensitive to, such as the high-resolution detail bands (LH, HL, and HH). Embedding watermarks in these regions allow us to increase the robustness of our watermark, at little to no additional impact on image quality [7]. The fact that the DWT is a multi-scale analysis can be used to the watermarking algorithm’s benefit.
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Color evaporation induced rapidity gaps

Color evaporation induced rapidity gaps

Our computation of gap rates using color evaporation is free of parameters and therefore predicts absolute rates, as well as their dependence on kinematic variables. In practice, this prediction is diffused by the necessity to introduce a gap survival probability S p , which accounts for the fact that genuine gap events, as predicted by the theory, can escape experimental identification because additional partonic inter- actions in the same event produce secondaries which spoil the gap. Its value has been estimated for high energy p p ¯ interactions to be of the order of a few tens of percent. The fact that the color evaporation calculation correctly accom- modates the absolute gap rate observed in p g collisions im- plies that S p 51. There is a simple explanation for this value. The dijet cross section is dominated by resolved photons. However, for resolved processes, a secondary partonic inter- action which could fill the gap is unlikely because it requires resolving the photon in 2 partons. Although this routinely happens at high energies for hadrons, it does not for photons.
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Color Image Reconstruction Using A New R'G'I Model

Color Image Reconstruction Using A New R'G'I Model

Direct and inverse conversions using the proposed model were tested using different images. The proposed conversion was tested using an original color image to get the gray image and without applying any processing we got the color image using inverse conversion, the experimental results showed that the correlation between the original image and the obtained color image was always equal one, which means full matching between the original image and the obtained one.

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New Time based User Security Scheme for Smart Cards

New Time based User Security Scheme for Smart Cards

Abstract- User Security is an important technology to guarantee that only the legal users can access resources from the remote server. The advantages of smart cards are storage and computation abilities. Recently, there are many remote user authentication protocols with smart card have been proposed to improve security, efficiency, and functionality extensively by many scholars. This article finds that R. C. Mittal ‘s scheme may suffer impersonate attack, and do not allow changing password freely for the user. Finally, we proposed an improved timestamp-based user authentication scheme. The modified method is more efficient and secure than R. C. Mittal scheme.
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