Abstract: 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.

Key words: Multiple secrets, Operational scheme, Threshold structure, Visual secret sharing, XOR