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Halftone visual cryptography is an encryption mechanism that a secret image is encoded into halftone shares for showing meaningful images. You only need to superimpose part of these share images. Then, images can be shown the original confidential. In this paper, we propose an encoding scheme to improve the efficiency of visual secret sharing technology. We use the relative location information of...
In this paper a multiple frequency domain steganography is proposed; it uses DWT (discrete wavelets transform) with DCT (discrete cosine transform) techniques, which are applied sequentially on the cover image. Embedding the secret message is done in the high frequency coefficients to provide a high imperceptibility; as it is the most important property of any steganography system. For secret message...
Presently, distributed video coding (DVC) arouse high research interests due to the distinct contribution to the low-complexity encoding. In this paper, we propose a hash-based DVC, where the hash bits are compressed by a rate-adaptive low density parity coding accumulate (LDPCA) and sent to aid the decoder in motion estimation. The hash bit-rate is ideally near to its conditional entropy, so we name...
Exponential growth of the internet provided new ways of propagating and sharing digital video data. Thus ownership protection of the video data is critical and important in this era. Though there are many standards and technologies available to efficiently share the digital video, almost all of them lack ownership protection mechanism. This paper proposes new compressed domain secure digital watermarking...
In this research, we aim to conceal a secret data Into the cover image without noticeable degradation. In our approach, Lempel-Ziv-Welch (LZW) compression and set partitioning in hierarchical trees (SPIHT) codec are used to obtain a low bit rate and high econstructed quality image compression. In the embedding process, an adaptive phase modulation (APM) mechanism and discrete Fourier transform (DFT)...
More and more researchers focus on the visual cryptography scheme that embeds more than one secret image. Most of them generate size-expanded transparencies for decoding only by human eyes. In this paper, a non-expansible flip-flop visual cryptography (FFVC) scheme is proposed. Firstly, stacking two generated transparencies, one of the secret images can be decoded. Another secret image can be decoded...
This paper proposes a new method to embed data in binary images, including scanned text, figures, and cartoon images. The proposed method is based on the manipulating of chains, which are a representation of binary image, to hide data. The chain records the edge information of an image, and the modifications of chains are modifications of edge area. It is difficult to be recognized by human eyes....
A vision system is used for measuring in-plane target position, displacement and orientation. An encrypted pseudo-periodic pattern fixed on the target forms a phase reference. Absolute position is determined with subpixel accuracy by phase computations from any local view of a small zone of the pattern. Method principle is presented and performances are characterized. The capability to resolve position...
Double phase encoding suffers from vulnerability to attacks such that brute force attacks and chosen plain text attacks. A method to improve the security of double phase encoding against those attacks is presented. The proposed method suggests placing an intensity image at the Fourier plane. This added Fourier plane modulation prevents an attacker from recovering the Fourier plane encryption phase...
The offered algorithm stability to illegal decoding fully corresponds to RSA algorithm stability. Nevetherless, according to practical utilization of described RSA modification, in the coded image we managed to achieve complete noising and avoid domains of similarity (Fig. 5). At the same time to display outlines of the sent image becomes practically impossible. It gave possibility to level possibilities...
Multi-pixel encoding is an emerging method in visual cryptography for that it can encode more than one pixel for each run. However, in fact its encoding efficiency is still low. This paper presents a novel multi-pixel encoding which can encode variable number of pixels for each run. The length of encoding at one run is equal to the number of the consecutive same pixels met during scanning the secret...
In visual secret sharing (VSS) schemes, a secret image can be visually revealed by overlapping shares. But the contrast of reconstructed image is much lost. A useful way to improve this situation is to employ reversing, a non-cryptographic operation supported by most copy machines, to reverse black and white pixels. Firstly, this paper gives a survey for current VSS schemes with reversing. Secondly,...
In order to avoid pixel expansion and contrast of the gathered secret image compromise, an easier visual cryptographic scheme, which was called visual cryptographic of interleaving with sub-block coding method, was presented. Instead of using m subpixels to represent one pixel, according to a key matrix, the secret image was divided into 2 shadow images, in which there were some background pixels...
Visual cryptography (VC) schemes hide the secret image into two or more images which are called shares. The secret image can be recovered simply by stacking the shares together without any complex computation involved. The shares are very safe because separately they reveal nothing about the secret image. In this paper, a color visual cryptography scheme producing meaningful shares is proposed. These...
This paper proposes a method to encrypt an image in two shares with following properties. (1) The method is suitable for binary, gray level or color image encryption. (2) The bit error rates are adjustable, and thus the secret image can be recovered to different extents including lossless and nearly lossless. (3) Sizes of the share images are flexible to be changed, and thus the method can be used...
It is the well-known visual secret sharing (VSS) technique that encrypts a secret image into several share images and, later, decrypts the secret by stacking the share images and recognizing by the human visual system. Due to the perfect secrecy, VSS is one of well-candidate for achieving secure e-commerce. Furthermore, the other visual secret sharing technique is constructed by random grids. The...
High payload information hiding schemes with the good visual quality of stego images are suitable for steganographic applications such as online content distribution systems. This paper proposes a novel steganographic scheme based on the (7, 4) Hamming code for digital images.The proposed scheme embeds a segment of seven secret bits into a group of seven cover pixels at a time. The experimental results...
A novel method of steganographic embedding is described based on vertex colorings in the grid graph, in which rainbow coloring is repeated in every block of cover signals to increase embedding efficiency. This is an improvement of the previous grid coloring method in steganography. It also outperforms LSB matching revisited method and direct sums of ternary Hamming codes. The proposed method can generate...
This paper generalizes the running coding method for efficient data hiding. In this way, each secret digit in a prime-base notational system is represented by a series of cover values. Modification on one cover value can be used to embed several secret digits, so that distortion is significantly reduced. The original running coding method can be viewed as a special case of the generalized scheme with...
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