| 摘要 |
PURPOSE: A method and a device for embedding and extracting a watermark to and from a text file are provided to embed watermark to sentences or words in a text file without any changes distinguished by a naked eye and extract the embedded watermark in spite of clustering errors. CONSTITUTION: A device for embedding a watermark to a text file includes a sentence analyzing part(120), a region selecting part(130) for selecting same characters having different character code values in a text file, a watermark generating part(140) for generating binary watermark bit stream signals, an error correcting code(150), an extension part(160) for extending the watermark bit stream signals with R-multiples, a key inserting part(170), a random number generating part(180) for generating binary pseudo random number signals of wide band from a predetermined user key, an XOR converting part(190) for XOR-operating the extended watermark bit stream signals and the binary pseudo random number signals to generate watermark bit stream signals of diffusion spectrum type, a shuffling part(200) and a combination part(210) for embedding the watermark to the text file by the equal characters having different character code values.
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