With aid of a X.509 certificate, you can sign and encrypt files.
First, you need to install a proper certificate management software on your computer. Here, the software called “Kleopatra” would be suitable, for example. Kleopatra is a free (in the sense of freedom), open source and free of charge software.
At first, you will need to import the two complete certification chains of DFN-PKI for the Jade University in Kleopatra. The necessary files can be found in the network system of computers within the university campus and via WebFiler from outside.
To do so, import the following files from the Kleopatra menu item „Datei / Importieren“ (ENG: „File / Import“) in the given order.
At the end, close all tabs with the name „Importierte Zertifikate“ (ENG: „Imported Certificates“). Only keep the tab „Alle Zertifikate“ (ENG: „All Certificates“) opened.
Certificate Revocation Lists
At the moment, certificate revocation lists are not being supported. This is why you need to deactivate the check:
In the further course, you need to import your X.509 certificate with aid of your certificate file, which has been created under backup:
Therefore, import the certificate file created under backup by going to the Kleopatra menu item „Datei / Importieren“ (ENG: „File / Import“). In the course of the import-dialogue, the window „pinentry“ asks you to type in a passphrase. A passphrase is the password you have already typed in under backup (it is possible that you will be asked to type in your password two more times).
Public User Certificates
In case you would like to encrypt files or e-mails for other persons, you must have the public user certificates of your recipient, which are necessary for encryption. You will also have to import them in Kleopatra.
Now you can sign and / or encrypt files in Kleopatra:
Now you can check files in Kleopatra for valid signatures and / or decrypt them: