Optimal Colored Threshold Visual Cryptography Schemes

Cimato, Stelvio; Prisco, Roberto De; Santis, Alfredo De

doi:10.1007/s10623-003-6741-z

Cited by 79 publications

(44 citation statements)

References 6 publications

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“…The papers [13,5,14,7] use a model that is very close to our own. The difference is that those papers allow pixels of the same color to be superimposed (assuming that the resulting color is still the same one).…”

Section: Introductionmentioning

confidence: 95%

“…This can be done either by requiring the special property that superimposing pixels with different colors one gets black [13], or by ensuring that we have at least one black pixel in the superposition (e.g. [14,7]). The artificial property used in [13] can be simulated by subdividing each pixel into c subpixels.…”

Section: Introductionmentioning

confidence: 99%

“…The schemes of [13,5] require the special property that superimposing two pixels of different colors one gets black, which can be implemented paying a loss of resolution of a factor equal to c. In [14,7] such a special property is not required because the schemes provided in those papers never superimpose pixels with different colors; hence the extra factor of c in the pixel expansion is avoided.…”

Section: Introductionmentioning

confidence: 99%

“…In [7] a tight lower bound on the pixel expansion of c-color (n, n)-threshold schemes has been provided. Such a lower bound is:…”

Section: Introductionmentioning

confidence: 99%

“…In [7] a construction of (contrast-optimal) c-color (k, n)-threshold scheme is also given and the resulting pixel expansion improves in some cases the one of [14].…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Colored Visual Cryptography Without Color Darkening

Cimato

Prisco

Santis

2005

Security in Communication Networks

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In a visual cryptography scheme a secret image is encoded into n shares, in the form of transparencies. The shares are then distributed to n participants. Qualified subsets of participants can recover the secret image by superimposing their transparencies. Non-qualified subsets of participants have no information about the secret image.In this paper we consider the case when the secret image is a colored image. Most of the previous work on colored visual cryptography allows the superposition of pixels having the same color assuming that the resulting pixel still has the same color. This is not what happens in reality since when superimposing two pixels of the same color one gets a darker version of that color, which effectively is a different color. Superimposing many pixels of the same color might result in a so dark version of the color that the resulting pixel might not be distinguishable from a black pixel.In this paper we propose a model where the reconstruction has to guarantee that the reconstructed secret pixel has the exact same color of the original one and not a darker version of it. We consider (k, n)-threshold schemes where a qualified set of participants consists of any k participants. We provide a general construction for any k, 2 ≤ k ≤ n and a construction for the special case k = 2.We also prove lower bounds on the pixel expansion (which is a measure of the goodness of the scheme) for the cases k = 2 and k = n. The lower bounds match the pixel expansion of the schemes provided in these two cases, thus proving that our schemes are optimal with respect to the pixel expansion. We also provide an upper bound on the contrast of (k, n)-threshold schemes and (2, n)-threshold schemes with optimal contrast.

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Section: Introductionmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…In [7] a tight lower bound on the pixel expansion of c-color (n, n)-threshold schemes has been provided. Such a lower bound is:…”

Section: Introductionmentioning

confidence: 99%

“…In [7] a construction of (contrast-optimal) c-color (k, n)-threshold scheme is also given and the resulting pixel expansion improves in some cases the one of [14].…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Colored Visual Cryptography Without Color Darkening

Cimato

Prisco

Santis

2005

Security in Communication Networks

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Color Visual Cryptography Schemes Using Linear Algebraic Techniques over Rings

Dutta

Sardar

Adhikari

et al. 2020

Information Systems Security

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Secure Two-Party Computation: A Visual Way

D’Arco

Prisco

2014

Lecture Notes in Computer Science

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In this paper we propose a novel method for performing secure two-party computation. By merging together in a suitable way two beautiful ideas of the 80's and the 90's, Yao's garbled circuit construction and Naor and Shamir's visual cryptography, respectively, we enable Alice and Bob to securely evaluate a function f (·, ·) of their inputs, x and y, through a pure physical process. Indeed, once Alice has prepared a set of properly constructed transparencies, Bob computes the function value f (x, y) by applying a sequence of simple steps which require the use of a pair of scissors, superposing transparencies, and the human visual system. A crypto-device for the function evaluation process is not needed any more.

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Optimal Colored Threshold Visual Cryptography Schemes

Cited by 79 publications

References 6 publications

Colored Visual Cryptography Without Color Darkening

Colored Visual Cryptography Without Color Darkening

Color Visual Cryptography Schemes Using Linear Algebraic Techniques over Rings

Secure Two-Party Computation: A Visual Way

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