Secret image sharing with enhanced visual quality and authentication mechanism

Abstract

Secret image sharing is a technique to share a secret image among n participants. Each participant has a meaningless, noise-like share. The image is revealed if any k of the shares are gathered. This scheme uses the polynomial based (k, n) secret sharing approach proposed by Shamir in 1979. In 2004, Lin and Tsai proposed a new secret image sharing method with steganography. Their scheme uses steganography to hide the shares into cover images. After this pioneering research, Yang et al. proposed a technique with enhanced stego image quality and better authentication ability in 2007. Wu et al. proposed another method to both decrease size expansion ratio of stego images and increase stego image quality by 0·5 dB compared to Yang et al.’s method in 2009. A new method with better authentication ability and stego image quality is proposed in this manuscript. More natural looking stego images of 43 dB peak signal-to-noise-ratio (PSNR) are generated by the proposed method exceeding Wu et al.’s method by 1·2 dB on the average. Also proposed method can detect fake stego blocks with probability 0·875 while other methods could detect with probability 0·5. The experimental results indicate enhanced authentication ability and visual quality compared to other methods.

Keywords:

• secret sharing
• steganography
• PSNR

This research was supported by the Research Fund of Karadeniz Technical University, (Project No: 2008·112·009·1). The authors would like to thank the reviewers for their valuable comments.