Proposal of a Lattice-based Visual Secret Sharing Scheme for Color and Gray-scale Images

Hiroki KOGA and Hirosuke YAMAMOTO

IEICE TRANS. FUNDAMENTALS, vol.E81-A, no.6, pp.1262-1269, June 1998.

  • The visual secret sharing scheme (VSSS) proposed by Naor and Shamir [1] provides a way to encrypt a secret black-white image into shares and decrypt the shares without using any computing power. This paper proposes an extension of VSSS to sharing of color or gray-scale images. In this paper ($k$,$n$) VSSS for images with $J$ different colors is defined as a collection of $J$ disjoint subsets in $n$-th product of a finite lattice. Any collections of $k-1$ shares reveal no information on the images. The subset can be constructed by solving certain simultaneous linear equations. In particular,the subsets are simply expressed in $(n,n)$,$(n-1,n)$ and $(2,n)$ cases.
  • Key words: secret sharing, visual secret sharing, cryptography
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