In Outlook, go to the File tab, go to Options and select in the Security Centre the Settings for the Security Centre in the Security Centre:

In the Email security sub-item, you can first make the setting „Add digital signature to outgoing messages“. This setting is recommended so that e-mail messages are signed by default. Also activate „Send signed messages as plain text“.

Then click on the button Import/Export….

In the window that opens, enter the path to your backup copy of the certificate, the password with which you have protected your backup copy and your name. Click ok.

In the following dialogue, please select the „Security level“ option

The „Medium“ option is selected by default.

We recommend the „High“ option. As a result, a protection password is requested when accessing the private key of the certificate, which is required for the signature. You must specify this in the next dialogue.

In the application, the private key is stored in Outlook until the next start, so you do not have to re-enter it for every email.

Click on Select…, a selection of imported certificates appears.

Click on Further options.

Select the certificate with the group mailbox xyz@haw-landshut.de and click OK to close the window.

In the window Change security settings window, under Hashalgoritumus select SHA256 under Hashalgoritumus.

You can now sign and encrypt messages. When creating a new message, you will find the options for encrypting and signing under „Options“. Signing should be set by default, so you don't need to do anything else.

You can only encrypt if you have previously entered the public key of the recipient beforehand. This works, for example, if the recipient has previously sent you a message signed by them. This usually contains their public key and you can reply to them in encrypted form.

English Version: SMIME with Outlook