关键词: 文本零水印, 特征提取, 相关函数, 鲁棒性, 透明性, 时间戳

Abstract: Aiming at the problems of difficult embedding of Chinese text digital watermark, poor imperceptibleness and robustness and lack of watermark capacity, a zero-watermark algorithm based on use frequency of Chinese characters was presented. In this algorithm, the use frequency of Chinese characters in the text was calculated, and then combining the frequency table of commonly used Chinese characters, the text characteristic was extracted to construct a zero-watermark. According to the trait of the watermark algorithm, a correlation function was defined to fix threshold value and examine the watermark. Experimental results indicate that the watermark algorithm constructed in this way has good imperceptibleness, robustness and sufficient watermark capacity, and the constructed watermark examining algorithm based on the correlation function exhibits comparatively lower misjudging rate.

Key words: text zero-watermark, feature extraction, correlation function, robustness, imperceptibleness, time-stamp