Improved Extended Polynomial-Based Secret Image Sharing Scheme Using QR Code

Abstract

Secret image sharing technology is an effective approach to encode the secret image into several shares, and the original image can be recovered by the remaining shares even some shares are lost. As a typical two-dimensional machine reada-ble code, QR code is widely used in human life due to its fast reading speed, high data density and strong error correction capability. Combined with the characteristics of QR code and secret image sharing, an extended secret image sharing scheme was proposed based on QR code, where "extended" means that the generated shares were visually similar to the QR code. The main idea is to control the parameters' selec-tion of polynomial using the binary QR codes. Meanwhile, the average gray difference of the shares was defined as α to measure the similarity between QR-like shares and the origi-nal carrier QR codes. Based on α, a secret sharing algorithm was designed to generate QR-like shares. At last, upper and lower limits of α are introduced through experimental analy-sis, and the relationship between the error correction level of carrier QR code and the lower limit of α.