Qubes PDF Converter is a Qubes OS application that uses DisposableVMs and Qubes' flexible qrexec (inter-VM communication) infrastructure to securely convert untrusted PDF files into safe-to-view PDF files.

This is done by using a DisposableVM to render each page of a PDF file into a very simple representation (RGB bitmap) that (presumably) leaves no room for malicious code. This representation is then sent back to the client qube which then constructs an entirely new PDF file out of the received bitmaps.

For more details, please see the article in which this concept was originally introduced:

http://blog.invisiblethings.org/2013/02/21/converting-untrusted-pdfs-into-trusted.html

[user@domU ~]$ qvm-convert-pdf file1.pdf file2.pdf file3.pdf
:: Sending files to Disposable VMs...

 file1.pdf...done
 file2.pdf...fail
 file3.pdf...done

Total Sanitized Files: 2/3

Original idea and implementation by Joanna Rutkowska. This application was subsequently incorporated into Qubes OS, and multiple other developers have contributed various fixes and improvements (see the commit log for details).