A new lossless secret color image sharing scheme with small shadow size

Though there have been many research works carried out on the grayscale secret image sharing schemes, there is not sufficient research work available on the field of color secret image sharing schemes, especially on the lossless secret image sharing schemes. In the current work, we propose a new lossless secret color image sharing scheme with small shadow size. We directly deal with the three components of the intensities of the RGB values of each color pixel of the secret image. Using a mathematical transformation, we first embed the RGB intensity values of each secret pixel as an element of a suitably chosen finite field F. Then the whole mathematical operations are carried over the finite field F to generate shares using k-1 degree polynomials in the polynomial ring F[x]. Unlike most of the image sharing schemes, we do not have the preprocessing stage in which the secret image is transferred into random image either by using Arnold Cat map or by using some chaotic maps to avoid residual image effect. From experimental simulations, it is evident that the measure of randomness of the shares generated using our algorithm is same as that of the shares generated using the preprocessing stage in which Arnold Cat map or chaotic map is used, resulting our scheme simpler and efficient. Moreover, our scheme produces shares having smaller size than the secret image. Finally the recovery of the secret image by the qualified set of participants is lossless. © 2020 Elsevier Inc.