These files have been created by encrypting the minimal.pdf file.
The used encryption algorithm as well as the key length is encoded
in the files name.

The prefix shows which if any password was used:
* nopwd: No password was set.
* userpwd: An user password of 'uhexapdf' has been set.
* ownerpwd: An owner password of 'ohexapdf' has been set.
* bothpwd: Both the above user and owner passwords have been set.
