A (t, n) Secret Sharing Scheme for Image Encryption

This paper introduces a new (t, n) secret sharing scheme for image encryption. The proposed method encrypts the secret image into two images as the same size of the original image, which one is the public image (called the encrypted image) and another is to be shared among n participants using a new secret sharing method based on the Shamir’s secret sharing. In the new secret sharing scheme, t (or more) shares secretly held by the participants could reconstruct the shared image, where the size of each share is 2(logtm)/m2 of that of the shared m*m  image. Then the secret image could be recovered from the encrypted image and the shared image through simple XOR operations without any loss. Furthermore, the size of the shares can become smaller by partitioning the secret image into many smaller blocks and encrypting all these block images into a public encrypted image as the same size of the secret image. Compared with the known image encryption schemes based on the secret sharing, the size of the shares in our scheme is smaller with the same size original image.