关键词: 文档水印, 泄密追踪, 抗打印扫描

Abstract:

As a kind of information leaking carrier, printed documents are recently becoming a large security risk. Tracing document with watermarks is an effective resolution to the problem. It is found out that the heights of neighboring characters from nature text are usually not the same, and most height relationships between character pairs keep reserved after print-scan. According to it, this paper proposes a new robust watermark method by modifying character's height. Besides, only those character pairs with similar complexity will be chosen to achieve better transparency. Experiments show that the watermark can be extracted from the texts distorted due to print-scan, print-copy, or print-photograph.

Key words: document watermark, information leak tracing, anti-printing