Q: I would like to distribute some PDF documents and I would like to
embed in those documents a custom security check that should pass a
"document code" to a web service
provided by me and, based on the return code of the web service,
should either open or close immediately (maybe also "auto-destroy" in
some way). The goal of my project is to
time-expire documents so that my customers should buy new versions
after a given period. The document should also be encrypted.
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A:
There is no 'standard' security mechanism in PDF that will allow
documents to 'expire' or to implement other custom security
behaviors.
You can use PDF viewer from PDFNet SDK (see http://www.pdftron.com/net/samplecode.html#PDFView)
to implement custom security permissions behaviors (such as time
expiration, the number of times a document can be printed, etc). You
can also use the same SDK to customize the viewing experience for your
reading audience (e.g. eBooks, CAD/CAM, interactive content, etc).
Using PDFNet SDK you can also insert custom properties and can modify
SDF.SecurityHandler so that your eBooks can be only viewed using your
PDF viewer. The custom viewer can be distributed as integral part of
eBook download, through 'one-click' deployment, or as a traditional
desktop application.