Improved Invertible Secret Image Sharing with Steganography

In 2010, Lin and Chan proposed an invertible secret image sharing with steganography scheme, in which each generated shadow image has natural appearance that conceals the track of the shared secret image elaborately. The method not only can reconstruct the secret image loss less but also can change the distorted cover image back to its origin version. It is practical for fulfilling image sharing with steganography scheme where the cover image is sensitive to alterations. However, the scheme suffers from an overflow problem in the case of embedding data in pixels with value greater than or equal to ⌈(2^k/p⌉×p in a k-bit cover image, where p is a prime number set in the sharing function, and some secret patterns were leaked from a single shadow image. In this paper an improved method of Lin and Chan´s invertible secret image sharing scheme is proposed. The scheme divides the input secret image into multiple sections with each section fits in an alpha-bit space, the sharing function is carefully designed to conceal the statistical property of the secret image properly, and all arithmetic operations are performed in power-of-two Galois Field GF(2^α). Experimental results show that the proposed scheme obtains better quality of shadow images, and the security property to the secret image is improved.