German (DE)
French (FR)PDF Security and Permissions / PDF Printer
Instead of this rather technical chapter on PDF security, users should instead go to the tutorial on this page...
When you protect your PDF documents with passwords you can optionally specify a set of permissions. The permissions determine which kind of access the user password will provide. Using the permissions you can prohibit the user from printing and using cut and paste operations. See the table below for a complete overview.
The table is part of the PDF reference (third edition). Go to www.adobe.com. for a complete reference.
| BIT POSITION | MEANING |
|---|---|
| 1-2 | Reserved; must be 0. |
| 3 | (Revision 2) Print the document. (Revision 3) Print the document (possibly not at the highest quality level, depending on whether bit 12 is also set). |
| 4 | Modify the contents of the document by operations other than those controlled by bits 6, 9, and 11. |
| 5 | (Revision 2) Copy or otherwise extract text and graphics from the document, including extracting text and graphics (in support of accessibility to disabled users or for other purposes). (Revision 3) Copy or otherwise extract text and graphics from the document by operations other than that controlled by bit 10. |
| 6 | Add or modify text annotations, fill in interactive form fields, and, if bit 4 is also set, create or modify interactive form fields (including signature fields). |
| 7-8 | Reserved; must be 1. |
| 9 | (Revision 3 only) Fill in existing interactive form fields (including signature fields), even if bit 6 is clear. |
| 10 | (Revision 3 only) Extract text and graphics (in support of accessibility to disabled users or for other purposes). |
| 11 | (Revision 3 only) Assemble the document (insert, rotate, or delete pages and create bookmarks or thumbnail images), even if bit 4 is clear. |
| 12 | (Revision 3 only) Print the document to a representation from which a faithful digital copy of the PDF content could be generated. When this bit is clear (and bit 3 is set), printing is limited to a lowlevel representation of the appearance, possibly of degraded quality. (See implementation note 16 in Appendix H.) |
| 13-32 | (Revision 3 only) Reserved; must be 1. |
* Source: PDF Reference / Adobe
A number of the bits listed above are reserved and must be 0 whereas others must be 1. If you combine all the mandatory reserved bits you get a decimal value of -3904. The number is negative because it is a signed integer. With that number as a base you can add the bit values of the permissions you want. Let's say you want the user to have print and copy permissions then you add bit 3 for printing and bit 5 for copy. The permission value is then -3904 + 4 + 16 = -3884.
It is important that you specify an owner password when using this security feature. User and owner passwords must be different. If they are the same then the user will have owner permissions, which means that the permission settings have no effect. You can leave the user password blank if you wish.
