Abstract: Two parameters, pixel expansion and contrast, are very important in visual cryptography. It’s very difficult to optimize both of them in theory. Based on permutation, a (2,n) scheme, which existence has been proved theoretically, is proposed. The method of construction has been carried out. Simulation results demonstrate that this scheme can balance performance between pixel expansion and contrast, i.e., when the contrast is close to optimality, the pixel expansion is relatively minor.

Key words: Visual cryptography, Visual secret sharing scheme, Visual threshold scheme(VTS), Permutation

摘要： 像素扩展度和对比度是视觉加密方案中两个重要的指标，同时使二者达到最优在理论上是非常困难的。运用排列的方法设计出一种(2，n)方案，从理论上证明了其存在性，并给出了该方案的构造方法。软件仿真结果表明，该方案能够折衷考虑二者之间的矛盾，在像素扩展度较小的情况下，使对比度接近最优。

关键词: 视觉加密, 可视秘密共享方案, 可视门限方案, 排列

CLC Number: 

• TP31