You can remove the encryption from the spdf doing this:
Download SplViewer (
www.lvbprint.de/html/splviewer.html) and install cutepdf or pdf995 or primopdf (whatever) in your pc, google it.
Disconnect your printer cable, open the .spdf file and print it in the printer you just disconnected. An error message is displayed because your printer is not connected, however the ".spl" file can be found at c:\windows\system32\spool\printers.
Open the .spl with the SplViewer and print it using pdf995 or cutepdf or whatever pdf virtual printer you want.
Done !!