The Design and Application of the Threshold Birthmark Algorithm based on Mutual Information Gain Rate

In order to resist the damage of digital text works in high BER networks or illegal copy in publication, we propose a robust feature-extracting algorithm based on threshold technology and then construct a new threshold birthmark algorithm. The information gain rate has been used to veraciously measure the importance of the feature in feature-extracting, and threshold(t,n) technology has also been used in constructing birthmark to reduce the cost and achieve good tolerance for different conditions. So the application based on this algorithm can overcome the text defect comes from bad channel or manual malicious modification. The method has been proven IND-CCA2 secure and robust. At the end of this paper we introduce a scheme of copyright protection based on this method.