摘要 |
A document authenticating method is disclosed by which numerous small-sized two-dimensional barcode stamps are generated and placed in a distributed manner on a printed document. The small-sized barcode stamps collectively encode the content of the document to be used for document authentication. In one example, the stamp size is about ¼ by ¼ inches or less and the tile size for the stamps is 4 by 4 pixels at a resolution of 400 dpi. The document is segmented into segments each containing a paragraph or a line of text. For each segment, a set of barcode stamps encoding the authentication data for the segment is placed in the vicinity of the segment. They may be placed in the empty space in the last line of each paragraph, in the empty space between adjacent paragraphs, or at the beginning or end of each line.
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