Summary
The 2018 International Symposium on Information Theory and Its Applications (ISITA2018)
2018
Session Number:Mo-PM-2-2
Session:
Number:Mo-PM-2-2.4
A Construction of the (4; n)-Threshold Visual Cryptography Scheme Using a 3-Design
Koutaro Okada, Hiroki Koga,
pp.223-227
Publication Date:2018/10/18
Online ISSN:2188-5079
DOI:10.34385/proc.55.Mo-PM-2-2.4
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Summary:
A (θ; n)-threshold visual cryptography scheme ((θ; n)-VCS) is one of secret sharing schemes for black-white images. In the (θ; n)-VCS, a dealer generates n black-white images called shares from a secret image by using two Boolean matrices called basis matrices. In this paper we propose a new construction of the basis matrices of the (4; n)-VCS using a combinatorial structure known as the 3-design. We establish validity of the obtained basis matrices and give formulas of the pixel expansion m and the relative difference αn of superimposed n shares. This construction can yield basis matrices with a much smaller pixel expansion than existing ones.