Use two simple commands to convert a protected pdf into an unprotected pdf.
Here in this example i assume the protected pdf file name to be ‘protected.pdf’.
Now open your terminal and type.
$ pdftops protected.pdf out.ps
$ pstopdf out.ps out.pdf
The out.pdf will be your unprotected PDF.
If you don’t have pstopdf and pdftops installed then type this at terminal to install them.
$ sudo apt-get install context
I’ve tried it on a DRM PDF and it doesn’t work. It prompted messages like
**** This file uses an unknown security handler.
**** The file was produced by:
**** ……
Error: ….
try pdf2ps…
Interesting, so I tried it and pdftops complains about not having the correct password. I wonder if it is version dependant?