| 摘要 |
<p>The present invention relates to methods for modifying ("watermarking") digital data such that any subsequent tampering with the data can be detected. The content data (which may be image data) is partitioned into subsections 11, 12, 13, 14. A secret key is used to associate items of the subsections into groups 22, 23, 24, each group including an item from each of the subsections. One item within each group is modified 33 using a value derived from all items in the group. Thus, watermarked data is produced. The invention is applicable to any form of data, but in particular to image data, which may be in the pixel domain or in a transformed domain.</p> |
