Abstract: This article firstly proposes a multi-secret sharing scheme，which will share t secrets and needs to solve t simultaneous equations.Then based on the multi-secret sharing ideal，we present a new（t，n）-threshold visual secret sharing scheme.The scheme splits a secret image into t sub-secret images，in which each sub-secret image’s size is 1/t of the original secret image;and then by t sub-secret images，computes n sharing images sent secretly n participants as the shares，which are the same size as the sub-secret images.So that any t or more shares can recover the secret image，but any t-1 or fewer of them gain no information about the original image.In addition，the recovered image is the same as the original secret image and there is no loss of the secret.The new scheme is secure and very efficient，which is a perfect（t，n）-threshold scheme to share b&w，gray-level or color images in a secret way.

Key words: visual cryptography, secret sharing, threshold schemes, multi-secret, perfect

摘要： 首先提出了一种多秘密共享方案，该方案共享t个多重秘密，需要计算t个联立方程。然后基于多秘密共享的思想，提出了一种新的（t，n）门限可视密码方案。该方案把一幅秘密图像分割成t幅子秘密图像，每幅子秘密图像是原始图像的1/t;然后再由t幅子秘密图像计算出n幅共享图像，秘密送给n个参与者，其中每个共享图像与子秘密图像同样大小。使得任意t个或更多的参与者合作能够恢复原始秘密图像，而任意少于t个参与者却得不到有关原始图像的任何信息。另外，恢复的图像和秘密图像完全一样，没有任何失真。新方案安全、有效，是一种完备的（t，n）门限方案，适用于把黑白、灰度、彩色图像作为秘密进行共享。

关键词: 可视密码, 秘密共享, 门限方案, 多秘密, 完备