Design of Gray Visual Cryptography Scheme Based on Quick Response Code

To improve the secret payload capacity of the quick response code with the basis of ensuring the decoding efficiency,an(n,n)XOR visual cryptography scheme oriented to grayscale image without size expansion has been proposed based on the module identification characteristics of the quick response code.It establishes the mapping relationship between the gray value and the series template according to the structure of the module identification unit,and then designs different sharing matrix sets of visual cryptography scheme to encrypt the secret image.Finally,Matlab and Photoshop are utilized to test and analyze the performance of the scheme.Experimental results and theoretical analysis show that the secret recovery algorithm of the proposed scheme is a linear time algorithm,the secret payload amount is 9 times as the specifications of the carrier image,and it can resist general geometric attacks such as compression,rotation and shear.