I downloaded the app and tried it out. They're saving files as regular PDFs with a .wwf extension. This causes the files to open in their app, but if you rename the file to .pdf you can open it in other PDF viewing apps just fine. They set a password on the PDF to restrict re-saving or printing.
Dumping the strings on their binary turns up genRandStringLength:, so I'm guessing they're generating a string of random characters and setting that as the password on the PDF.
They're just shipping a modified version of Skim (http://skim-app.sourceforge.net) embedded inside their own app to do the PDF viewing.
Dumping the strings on their binary turns up genRandStringLength:, so I'm guessing they're generating a string of random characters and setting that as the password on the PDF.
They're just shipping a modified version of Skim (http://skim-app.sourceforge.net) embedded inside their own app to do the PDF viewing.