Questions tagged [visual-cryptography]

Encrypting images so that they can be decrypted without using a computer, e.g. by superimposing two random-looking images.

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How can blockchain ensure uniqueness of a digital asset like a photograph?

If I take a picture with my beloved camera, the RAW file can be put into a blockchain, and thus it will have a unique hash. If that unique hash is ever spotted anywhere we know it's a copy of my ...
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Security of (2,2) Shamir's visual secret sharing scheme : How are the 2 shares random?

From the Visual Cryptography by Shamir and Noar. Let us take the pixel expansion as 2. Therefore, each pixel will be represented by 2 pixels (also called as subpixels) in a share. Since this is a (2,...
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Extracting the hidden text off an image embedded with steganography

Is it possible for me to extract the hidden text off a stego-image without using the same application that the hidden text was hidden with. I used 5 applications that do steganography such as, ...
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99 views

Number of possible access structure with $n$ person

I want to count number of possible access structures in closed form(if possible) as a variable of $n$,the number of share holder. I have tried in several ways. Still no good progress. It is very hard ...
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Apply visual cryptography to a video stream?

I read that there are different ways to apply visual cryptography. One is to generate two images that when overlapped provide the original image. The main issue of using this approach with a video is ...
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388 views

Need of Image Encryption [closed]

Question is simple yet confusing, why there is the need for image encryption. How text encryption is different from image encryption if using same technique like AES, DES, Chaotic algorithm. If the ...
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Algorithms of steganography [closed]

Recently I'm working on steganography and I want to know that what are the main steganography algorithms and how they work. I'll be happy if you help me. thanks.
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Is there a cipher related to colors and letters?

I was just wondering if a cipher existed where a number of symbols were colored with different colors forming a cipher?
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497 views

Is my high school cryptography/steganography science fair project practical?

I'm a 12th grade student interested in a science project in cryptography and steganography for my school's science fair. I chose this path of computer science partly because my coding skills are weak (...
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683 views

Can a QR code be scanned if split using visual cryptography?

I'm trying to get a python script to work such a way that it takes a QR code (a jpeg or a png) splits the jpeg into two images as shown here https://github.com/LessonStudio/VisualCryptography I'm not ...
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Why the light contrast of a set $\mathcal{E}$ of VCRG produced by an encryption scheme for a binary image B is defined as follows

In the paper “Image encryption by multiple random grids”, Shyong Jian Shyu, 42(7):1582-1596,· July 2009, the light contrast of a set $\mathcal{E}$ of VCRG produced by an encryption scheme for a binary ...
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The role of the dealer in visual cryptography

In visual cryptography schemes (VCS), there is special person called dealer. The dealer sets up the system, and the only one who knows about secret image. After encryption, the dealer distributes the ...
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Can you explain “k out of n” from the VCS paper by Naor and Shamir

I am new to visual cryptography. I’ve just read the paper “Visual Cryptography” by Moni Naor and Adi Shamir and I'm stuck on the chapter about the “$k$ out of $n$” construction. I am aware that, on ...
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Explanation of vector in Visual Cryptography

I'm starting to study about visual cryptography, but I am stuck with the following problem. On paper "Visual Cryptography" by Moni Naor and Adi Shamir, on page 6. How to read/what is the meaning of $...
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How can you produce visual cryptography?

I would like to be able to "code" images such as the one seen here on Wikipedia. Is this generally produced with software, or does this require complex programming? Ideally, I would love to be able ...
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Explanation of part of a visual cryptography algorithm

I have been working on a project involving visual cryptography and I am stuck with the following problem. My question is related to this paper, AN IMPROVED VISUAL CRYPTOGRAPHY SCHEME FOR SECRET ...
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442 views

Reusing message in One Time Pad

One of the main rules of the OTP is, that a key should never ever be reused. But if we use some commutative operation (XOR for example) for generating the cipher text, then I don't see any difference ...