Magic Sheet: Visual Cryptography with Common Shares

1Japan Advanced Institute of Science and Technology

CVM 2018

representative image

Abstract

Visual cryptography (VC) is an encryption technique for hiding a secret image in distributed and shared images (referred to as shares). VC schemes are employed to encrypt multiple images as meaningless, noisy patterns or meaningful images. However, decrypting multiple secret images using a unique share is difficult with traditional VC. We propose an approach to hide multiple images in meaningful shares. We can decrypt multiple images simultaneously using a common share, which we refer to as a magic sheet. The magic sheet decrypts multiple secret images depending on a given share. The shares are printed on transparencies, and decryption is performed by physically superimposing the transparencies. We evaluate the proposed method using binary, grayscale, and color images.

Results

Results

Result for grayscale images. The bottom secrets are decrypted by superimposing the corresponding cover images listed above them.

Dice Art (Dragon)

Result for color images. The bottom secrets are decrypted by superimposing the corresponding cover images listed above them.

Transformation Sequence

Resulting patterns printed on transparencies using a commercial inkjet printer. Top: simulation. Bottom: photo.

Transformation Sequence

More images. Our method can be applied to more images.

Links

Acknowledgements

We thank all reviewers for their helpful comments. This work was supported by JSPS KAKENHI Grant numbers 17J04232 and 16K12433.

Bibtex

@article{Kita:CVM:2018,
  title = {Magic sheet: Visual cryptography with common shares},
  author = {Kita, Naoki and Miyata, Kazunori},
  journal = {Computational Visual Media},
  year = {2018},
  month = {Jun},
  day = {01},
  volume = {4},
  number = {2},
  pages = {185--195},
  issn = {2096-0662},
  doi = {10.1007/s41095-018-0108-x},
  url = {https://doi.org/10.1007/s41095-018-0108-x}
}