| 摘要 |
The present invention relates to securing files that are derived from secured files. In general, a secured file can only be accessed by authenticated users with appropriate access rights or privileges. Each secured file is provided with a header portion and a data portion, where the header portion contains, or points to, security information. The security information is used to determine whether access to associated data portions of secured files is permitted. The improved approaches of the present invention can thus impose security on files that are derived from secured files. In one embodiment, files that are deemed derived from a secured file include files that are copies of the secured file. In another embodiment, files that are deemed derived from a secured file include files having content substantially similar to the content of the secured file. <IMAGE>
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