This paper presents a predictor-based watermark scheme that embeds secret bit streams and a DSA signature into an image. For the copyrighting of digital media, a DSA signature is appropriate as a watermarking technique. To improve security, we apply an Arnold transform (AT) to secret messages. We propose new predictors, Left-Top , which the predict current pixel values using neighboring pixel values. Our proposed scheme conceals secret messages by using the difference between current pixel values and predictive pixel values. Experimental results show that our method has low complexity and achieves a higher embedding performance with good perceptual quality compared to the earlier arts. Experimental results verified our proposed watermark method in multimedia communications.

Recently, Rey proposed an efficient (2,n) matrix- based secret image sharing (MSIS) scheme based on simple binary matrix operations. However, the threshold property of Rey's (2,n)-MSIS scheme is compromised. Elsheh and Hamza showed a weakness that if the ranks of the singular matrices used in Rey's scheme are not low enough then one can retrieve the secret information from only one shadow image. In this paper, we overcome this weakness. Our new (2,n)-MSIS scheme satisfies the threshold condition, and has low computational complexity for recovery.