Cryptography Reference
In-Depth Information
6
XOR-Based
Visual Cryptography
Daoshun Wang
Tsinghua University, China
Lin Dong
Tsinghua University, China
CONTENTS
6.1
Introduction :::::::::::::::::::::::::::::::::::::::::::::::::::::: 155
6.2
Preliminaries ::::::::::::::::::::::::::::::::::::::::::::::::::::: 156
6.3
Visual Cryptography Scheme Using the Polarization of Light :: 158
6.3.1
(2, n) Scheme :::::::::::::::::::::::::::::::::::::::::::: 158
6.3.2
(n, n) Scheme :::::::::::::::::::::::::::::::::::::::::::: 159
6.3.3
(k,n) Scheme :::::::::::::::::::::::::::::::::::::::::::: 159
6.4
Visual Cryptography Scheme with Reversing ::::::::::::::::::: 168
6.4.1
(k, n) VC Scheme Using Cyclic-Shift Operation :::::::: 168
6.4.2
A Scheme for General Access Structure ::::::::::::::::: 171
6.5
Secret Sharing Scheme Using Boolean Operation ::::::::::::::: 174
6.5.1
(2, n) Scheme :::::::::::::::::::::::::::::::::::::::::::: 175
6.5.2
(n, n) Scheme :::::::::::::::::::::::::::::::::::::::::::: 176
6.5.3
(k, n) Scheme :::::::::::::::::::::::::::::::::::::::::::: 178
6.6
Conclusion :::::::::::::::::::::::::::::::::::::::::::::::::::::::: 181
6.1 Introduction
A (k;n) visual cryptography (VC) scheme [16] is a type of secret sharing
scheme with the special property that a secret image can be recovered visually
by the human eye and does not require any calculation on a computer. How-
ever, the recovered secret image has low quality. In this case, some researchers
attempt to consider other different approaches to improve the quality (con-
trast) of the recovered image.
Lee et al. [12] presented a VC scheme using an XOR process to share a bi-
nary image. Since phase masks were placed on any path of the Mach-Zehnder
interferometer for reconstruction, the method is impractical and expensive
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