> Unfortunately, he is apparently not aware that tampering a "protected" > Acrobat file is not much more difficult than tampering any other data on > your computer. Many have asked me by private mail how comes... I think my answer is of interest for the whole list. <reference http://lava.instinct.org/fravia/zeropdf.htm> - However, here is a note from the PDF specs: "Despite the specification of document permissions in a PDF file, PDF cannot enforce the restrictions specified. It is up to the implementors of PDF viewers to respect the intent of the document creator by limiting access to an encrypted PDF file according to the permissions and passwords contained in the file." This means that a reader can ignore the permission settings. Unfortunately, this nice feature is missing from Acrobat Reader so we have to work a bit. </reference> Those on the Debian mailing list have witnessed anyway the recent discussion about a patch for xpdf which renders pdf protection useless (http://www.debianplanet.org/debianplanet/article.php?sid=146&mode=thread&or der=0 ); the author of xpdf has decided to honour Adobes futile attempt and not include the patch in the standard distribution. Anyway, it shows how utterly insecure this is (annoying for honest users, no obstacle for the others). If you want to quickly bypass encryption/passwords ina pdf file, go to http://www.ozemail.com.au/~geoffk/pdfencrypt/ and follow the instructions. As always, security through obscurity is worthless, just a nuisance. Anyway, as long as you can print a pdf, you can simply print it to a postscript file, modify it, and recreate the now modified pdf file. See, absolutely no gain in security by using pdf. Horst ================================================== Never ascribe to malice what can be explained by incompetence. --Anon ==================================================
