Tuesday, May 05, 2009
PDF with DRM
PDFZone discusses ProtectedPDF, a way of incorporating digital rights management in PDF. According to the article, ProtectedPDF files can be read in Acrobat Reader without any plugins, which presumably means that the files are fully PDF-compliant. Internet access to Vitrium's server is required to open documents. While the article doesn't say so, the only way I can think of doing this is through JavaScript.
The value or abusiveness of DRM depends on how it is used. For short-term use of a document, it can be a sensible way of limiting access. For limiting the distribution of content while supposedly allowing recipients permanent access, it doesn't work so well. If Vitrium ever goes out of business or gets tired of supporting ProtectedPDF, then all the rights-managed documents become inaccessible. "Buying" DRM-protected content, as opposed to renting it, is a dubious proposition. The effectiveness of DRM is limited; if you can get content on your computer, there's always a way to copy it.
Assuming JavaScript is required, users must enable it to view ProtectedPDF documents. (A third-party FAQ confirms this.) This exposes users to JavaScript-based vulnerabilities in Acrobat Reader, as well as possible loss of privacy. The article notes that ProtectedPDF files can report back on who's reading them. People are aware of these risks when using a web browser, less so when using a PDF reader.
As a technical concept, it's very interesting that DRM can be implemented within the PDF specification. How it works out in practice remains to be seen.
Labels: PDF
