This is a mirror of http://akira.arts.kuleuven.ac.be/andreas/blog/archives/2006/04/circumvent-pdf-drm-with-gmail.html which is down ATM due to the digg effect.
Apparently, Gmail's built-in "View as HTML" functionality, which allows you to view the content of PDF files (and other types of documents) as if they were classic webpages, works regardless of the files' usage restrictions (= DRM). I don't think this is a bad thing but just wonder how Google can back up this design decision, or is it a mistake?
You can try this out yourself:
Create or download a DRMed PDF file. I used this file from the Adobe site.
Open the file with Adobe Reader and click on the "Lock" icon in the down-left corner to see which restrictions apply. Our example file can be printed, but editing or text extraction is not allowed.
Send the file as an attachment to your Gmail account.
Open the mail you've sent yourself and choose the "View as HTML" option below the (empty) mail body.
An HTML version of the encrypted file is displayed, part of the layout might be gone, but the text can be extracted with a simple copy/paste command. In case the original PDF file had printing restrictions, those are stripped as well.
Note 1: a quick test with a PDF file with print restrictions yielded similar results; Gmail converted the file in question without any problem.
Note 2: Google Search on the other hand does comply with the copy restrictions inside PDF files; this search query for instance gives only non-encrypted PDF files a "View as HTML" option.