An EVCS for Color Images with Real Size Image Recovery and Ideal Contrast Using Bit Plane Encoding

Abstract

Conventional visual secret sharing schemes generate noise-like random pixels on shares to hide secret images. It suffers a management problem, because of which dealers cannot visually identify each share. This problem is solved by the Extended Visual Cryptography scheme (EVCS). However, the previous approaches involving the EVCS for general access structures suffer from a low contrast problem. This paper proposes a new (k,n)-threshold image sharing scheme using extended visual cryptography scheme for color images based on bit plane encoding that encrypts a color image in such a way that results of encryption is in the form of shares. Shares do not reflect any information directly, information is scrambled instead. The traditional binary EVCS is used to get the sharing images at every bit level of each principle component of a color image. This scheme provides a more efficient way to hide natural images in different shares. Furthermore, the size of the hidden secret can be recovered by inspecting the blocks in the shares. This new scheme for color images gives the ideal contrast in the recovered image.

Color Image Visual Secret Sharing with Expressive Shares using Color to Gray & Back and Cosine Transform

“…K Rajput [25] proposed a color image scheme using an Extended Visual Secret Sharing (EVSS) scheme for a recovered image with better contrast. Shares are generated by bit-level encoding for R, G, and B components using EVSS.…”