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There are different possibilities to use the electronic signature and encryption in the e-mail environment, depending on the software one is used to. Some prefer comfortable e-mail clients at the computer (e.g. Microsoft Outlook, Mozilla Thunderbird) or mobile versions (e.g. mit K-9 Mail), others work with Webmail via webbrowser.
A comfortable option to use e-mail encryption and an electronic e-mail signature on the computer would be to use the e-mail client Microsoft Outlook.
The operation system Microsoft Windows saves user certificates in a centralised location, the Cryptographic Service Provider. Microsoft Outlook expects user certificates at this exact location, this is why it is necessary to examine, whether the user certificate exists there:
Here, the personal user certificate that has been applied for should be visible. In case it is not (e.g. because you have not applied for the user certificate with the Internet Explorer), you will need to import the backup file created under User Certificates by clicking the button “Import“.
In the next step, Microsoft Office needs to know, which certificate is supposed to be used in which way:
In the third and last step, Microsoft Outlook should be set up for the comfortable use of digital signatures and encryptions:
Principle: You sign your e-mail with aid of your private key. The communication partner is then able to use your public key to check whether data exist unchanged.
Principle: You encrypt your e-mail with aid of the public key of your communication partner. Your communication partner is then able to decrypt the e-mail with his / her private key.
Hence, you need to have the public key of your communication partner in order to execute encryption: