The alignment problem of visual cryptography schemes

  • Authors:
  • Feng Liu;Chuan Kun Wu;Xi Jun Lin

  • Affiliations:
  • The State Key Laboratory of Information Security, Institute of Software, Chinese Academy of Sciences, Beijing, China 100190 and Graduate School of Chinese Academy of Sciences, Beijing, China 10019 ...;The State Key Laboratory of Information Security, Institute of Software, Chinese Academy of Sciences, Beijing, China 100190;The State Key Laboratory of Information Security, Institute of Software, Chinese Academy of Sciences, Beijing, China 100190 and Graduate School of Chinese Academy of Sciences, Beijing, China 10019 ...

  • Venue:
  • Designs, Codes and Cryptography
  • Year:
  • 2009

Quantified Score

Hi-index 0.00

Visualization

Abstract

Pixel expansion is an important parameter for Visual Cryptography Schemes (VCS). However, most papers in the literature are dedicated to reduce pixel expansion on the pixel level, i.e. to reduce the number of subpixels that represent a pixel in the original secret image. It is quite insufficient since the final size of the transparencies of the VCS is affected not only by the number of the subpixels, but also by the size of the subpixels in the transparencies. However, reducing the size of the subpixels in the transparencies results in difficulties of alignment of the transparencies. In this paper, we consider the alignment problem in VCS, and prove that in order to visually recover the original secret image, it is not necessary to align the transparencies precisely. This study is restricted to the case when only one transparency is shifted.