一种面向门限结构的操作式可视多秘密分享方案

Operational Visual Multi-secret Sharing Scheme for Threshold Structure

可视秘密分享将数字图像处理和秘密共享相结合,将秘密图像加密成多个共享份,在秘密恢复时将符合条件的共享份进行叠加,通过人眼直接解密秘密信息,具有解密复杂度低、信息容量大等优点。特别地,可视多秘密分享可用于分享多幅秘密图像,可应用于群体参与或控制领域。然而,目前操作式分享方案的研究受限于(2,2,n)存取结构,即n个参与者中的任意2个拿出持有的共享份进行恢复时,通过旋转和叠加操作最多能恢复2幅秘密图像。文中针对现有多秘密分享方法仅局限于两个参与者的问题,设计了一种新的秘密分享和共享份旋转操作规则,通过对秘密图像进行纵向区域划分,采用异或(XOR)运算基础矩阵对像素点逐区域进行加密,在此基础上设计了面向门限结构的操作式多秘密分享方案,并通过理论证明了方案的安全性和有效性。实验结果表明,与已有方案相比,所提方案通过在秘密分享时对秘密图像进行划分和标记纵向区域,实现了所有共享份地位对等,提高了可分享秘密的数量,最多可以同时将WT幅秘密图像分享到k个环形共享份中。该方案在满足安全条件的前提下,增强了相对差,改善了秘密图像的恢复效果。

Visual secret sharing(VSS)combines digital image processing with secret sharing.It encodes the secret image into multiple shares.Then the secret information can be decoded by human eyes directly when the qualified shares are superimposed.It has the merits such as low decoding complexity and large information capacity.In particular,visual multi-secret sharing(VMSS)can be used to share multiple secret images and applied to the field of group participation and control.However,the current research on operational sharing schemes is limited by the(2,2,n)access structure,that is,when any 2 of the n participants take out their shares for recovery,2 secret images at most can be recovered through rotation and superposition operations.Aiming at the problem that existing multi-secret sharing schemes are limited to 2 participants,a new secret sharing and sharing rotation operation rule is designed in this paper.By partitioning the secret image longitudinally and encrypting the pixels region by region with XOR basic matrix,an operational visual multi-secret sharing scheme(OVMSS)oriented to threshold structure is designed.Moreover,the security and validity of the scheme are proved theoretically.The experimental results show that,compared with the existing schemes,the proposed scheme achieves the equality of all shares by dividing secret images and marking the vertical regions in secret sharing,and improves the number of secrets that can be shared.WT secret images can be shared into k ring shares simultaneously at most.On the premise of meeting the safety conditions,the proposed scheme enhances the relative difference and improves the recovery quality of secret image.