Shadow size reduction and multiple image secret sharing based on discrete fractional random transform

This study proposes an improved image secret sharing scheme based on the discrete fractional random transform. In this (r, n)-threshold prototype, the shadow size is reduced to l/r of the secret image. In contrast, all shadows are of the same size as that of the secret image in the original scheme. Consequently, much storage space and transmission time is saved. Besides, our scheme can be naturally extended to multi-image secret sharing, i.e., r secret images can be encrypted in n shadows at a time. Meanwhile, the security is perfectly preserved due to the randomness of the discrete fractional random transform. Experimental results demonstrate the effectiveness of our scheme.