In the following we will explain how you can store an e-mail certificate, also called S/MIME, in your e-mail client. In our example we use the e-mail client Outlook.
Delivery of your certificate
After successfully ordering your S/MIME certificate via our website, you will receive an e-mail from the certification authority. With this e-mail you confirm the correctness of your order and verify yourself to them. After successful verification, the certification authority issues your certificate and delivers it to you by e-mail.
Formatting your certificate
You will receive the delivered certificate in .CRT format. Depending on the operating system you are using (Windows in our example), you may need to convert the certificate to another format, as Windows only works with px7 or px12 formats. This formatting can be done either by a server (like Linux) with OPENSSL or by a converter. An example for a windows based converter is Kleopatra.
Download Kleopatra
You can download Kleopatra / Gpd4win from the following link: https://www.gpg4win.org/download-de.html
Please always install the latest version here.
Administration of your certificate in Kleopatra
Kleopatra is a windows-based management software (integrated in Gpg4win), which supports you in signing your e-mails. You can easily insert the purchased S/MIME SSL certificate into Kleopatra using the "Import" function and manage it from there.
After the import, you can then export the certificate in the format you need. Please note that you should provide the certificate with a password to prevent misuse. If necessary, you still have to store a corresponding certificate of the certification authority under Windows. You can do this under Start → Search → Internet Properties under Contents → Certificates → Import.
After successfully storing all certificates, you now have the option in your e-mail program to sign your e-mails with the corresponding certificate in the trust center.