Scalable Secret Sharing of Compressed Multimedia

Secret Image Sharing

The proposed method is a simple, efficient and semantically secure (k, n) threshold secret image sharing scheme. In this scheme, we first encrypt the secret image using a stream cipher. To perform encryption we utilize the DCT coefficients in the compressed domain and the pixels values of the image in the uncompressed domain. For encryption we add the DCT coefficients with the pseudo random numbers in the compressed domain and for pixels in the uncompressed domain. The encrypted images are further partitioned into fragments using Reed Solomon error correction scheme. The seed used to generate the pseudo random numbers is also secret shared. The fragments of the image and the shares of the seed are distributed to the users. The secret image is reconstructed when any k shares are available to the users.

We have used libjpeg, opencv libraries to perform experiments on images. Below we show images of the shares generated along with the secret images