基于随机栅格的异或区域递增式视觉密码方案

XOR-Based Region Incrementing Visual Cryptography Scheme by Random Grids

针对现有区域递增式视觉密码方案仅局限于或运算,导致秘密图像中白像素无法被正确恢复的问题,给出了基于异或运算的区域递增式视觉密码的定义.通过迭代基于随机栅格的(k,k)单秘密视觉密码方案,利用0是异或{0,1}群中单位元的特性,设计了适用于异或运算的(k,n)单秘密方案的共享份生成算法,并构造了(k,n)区域递增式方案的秘密分享与恢复流程,分享过程中对于原像素s,依据s所在区域的密级,通过随机选取一个授权子集Q对s重新赋值,并利用(k,n)单秘密方案完成像素加密.恢复过程同一般视觉密码方案相同,最后对方案的有效性进行了理论证明.实验结果表明,该方案不仅实现了像素不扩展,且所有共享份叠加时白像素可以完美恢复.

Considering the problem of the white pixels in secret images can not be correctly recovered,which is resulted by the OR operation confined in exiting region incrementing visual cryptography schemes,a novel definition of region incrementing visual cryptography based on XOR operation is proposed for the first time.By iterating random-grid-based（k,k）single-secret visual cryptography scheme and combing the property of 0as the generator of the {0,1}group,the shares generation algorithm of（k,n）single-secret-sharing scheme using XOR operation is designed,and the secret sharing and recovering procedures for region incrementing scheme are proposed further.For any original secret pixel s,according to the security level,s is reassigned associated with a randomly chosen qualified set Qin the sharing procedure,and then encoded by the proposed（k,n）single-secretsharing scheme.The recovering procedure is the same as that of the previous schemes.The effectiveness is theoretically verified at last.Experimental results show that the present scheme not only realizes no pixel expansion,but also can obtain the perfect recovery of white pixels when all the shares are stacked.