... Gaussian distribution, and wecan obtain the lower bound for N. According to EmpiricalRule, about 99.73% of all values fall within three standarddeviations of the mean. Hence, to recognize a ... B(k,n)is a random matrix, namely, A 1|w, A 2|w, , A k|ware all randomand all independent of each other. With less than k shares,no information about the secret image is revealed, thus ... Greyscale and colour visual cryp tography,M.S.thesis, Computer Science of Dalhousie University-Daltech,Halifax, Canada, 1999.[12] C. Blundo, A. De Santis, and M. Naor, “Visual cryptographyfor...