-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Florian Kulzer wrote: > On Tue, Mar 13, 2007 at 02:33:04 -0500, Ron Johnson wrote: >> -----BEGIN PGP SIGNED MESSAGE----- >> Hash: SHA1 >> >> On 03/13/07 01:16, Joe Hart wrote: >> [snip] >>> Since you know so much about PDF files, let me ask you another >>> question. Does PDF have DRM capabilities built in? >> They can be password encrypted. Don't know about anything else. > > There are two different things: > > 1) A "user password" can be set. That means that the document is > encrypted and you need the password to open the document. The old > standard was 40bit encryption (due to US cryptography export > restrictions) which can be brute-forced in quite a short time with > modern computers. The new standard is 128 bit encryption. > > 2) An "owner password" can be set. This can be used to restrict what the > user can do with the document. You can for example disallow printing > totally, only allow low-quality print-outs or prevent the user from > copying the content of the document. These restrictions have to > honored by the PDF reader, of course. Most open-source readers either > ignore the DRM restrictions or give you an easy way to turn them off; > KPDF, for example, has an "Obey DRM restrictions" option which can be > unchecked. (In the worst case you can find the DRM check in the > source code, comment it out and recompile.) I believe that this is in > violation of Adobe's licensing terms for the PDF standard, which > AFAIK require that you implement the DRM if you code a PDF reader > based on their specifications. > > Option 1) and 2) can also be combined, of course. > > It is furthermore possible to write custom plug-ins which impose > additional restrictions. For example, we once got a reprint-PDF for an > article that we had published in a scientific journal. This PDF required > a plug-in so that it could contact the publisher's server to make sure > we could only print 50 high-quality copies of the paper. Needless to > say, this plug-in was only available for Windows. A nice way to take the > "P" out of PDF... >
Thank you for the insight. My opinion of Adobe hasn't changed. PDF files are a pain, and they do or can have (which is what I thought) DRM restrictions. At least I know if I use open source tools to manipulate the files, I can get around some of them. As for acroread goes, it has turned into a huge package. The version in my apt-cache shows 7.0.9, which is not the newest version, and it's a whopping 22911748 bytes. I imagine that 8.0 is even bigger. While KPDF may not be as feature rich, it does the job, and weighs in at 742592 bytes, and can embed nicely into konqueror. Joe - -- Registerd Linux user #443289 at http://counter.li.org/ -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFF9nufiXBCVWpc5J4RAkk0AJ9kn39IVNuFa8FdPqp0c9hLZ1yicACfaWcL I87Oy7aU+3G33jMECTIdPys= =/IWQ -----END PGP SIGNATURE----- -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
