Multi-layer Progressive Secret Image Sharing

This paper proposes a special type secret image sharing method. Based on the theories of secret image sharing and frequency domain transform, a multi-threshold secret image sharing is achieved. The method contains more properties compared with conventional secret image sharing which just has only one threshold. The properties of the proposed method include fault tolerance, small size of shares, secure, multi-threshold and progressive transmission. The method not only has the advantages of conventional secret image sharing, but also is more flexible. Users can set several thresholds in the method. When the number of shares is less than the smallest threshold, no secret will be revealed. While the numbers of shares collected are more than smallest threshold, a low quality secret image will be revealed. The quality of recovered secret image will be better after collecting more shares. When the amount of shares is over the maximum threshold, the recovered secret image is the same as the original secret image. Key-Words: Secret sharing, Progressive, Share, Fault-tolerance, Threshold, Transmission