Paper 1996/013 Original: eprint.iacr.org/1996/013 ↗
On the Contrast in Visual Cryptography Schemes
Abstract
A visual cryptography scheme is a method to encode a secret image SI into shadow images called shares such that certain qualified subsets of shares enable the ``visual'' recovery of the secret image. The ``visual'' recovery consists of xeroxing the shares onto transparencies, and then stacking them. The shares of a qualified set will reveal the secret image without any cryptographic computation. In this paper we analyze the contrast of the reconstructed image in k out of n visual cryptography schemes. (In such a scheme any k shares will reveal the image, but no set of k-1 shares gives any information about the image.) In the case of 2 out of n threshold schemes we give a complete characterization of schemes having optimal contrast and minimum pixel expansion in terms of certain balanced incomplete block designs. In the case of k out of n threshold schemes with k>2 we obtain upper and lower bounds on the optimal contrast.
Metadata
- Available format(s)
PDF- Publication info
- Preprint.
- History
- 1996-09-25: last updated
- 1996-09-25: published
- Short URL
- https://ia.cr/1996/013
- License
- https://creativecommons.org/licenses/by/4.0/
BibTeX
@misc{cryptoeprint:1996/013,
author = {Carlo Blundo and Alfredo De Santis and Douglas R. Stinson},
title = {On the Contrast in Visual Cryptography Schemes},
howpublished = {Cryptology {ePrint} Archive, Paper 1996/013},
year = {1996},
url = {https://eprint.iacr.org/1996/013}
}