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Signing and encrypting e-mails 

Employees of the University of Cologne can use S/MIME (Secure Multipurpose Internet Mail Extensions) certificates for e-mail signing and encryption, document signing . Use requires a personal certificate, which can be applied for online. Students are excluded from the use, unless they are SHK, WHB or WHK.


Instructions for applying can be found on our website.


Importing (and using) the S/MIME certificates differs in different email clients. Below you will find instructions for Mozilla Thunderbird, Microsoft Outlook, Apple Mail and Mail on iOS. For Android, there is currently no free email app or one that is integrated into the operating system that can handle S/MIME and is easy to configure (if you are still interested in using S/MIME in Android, please contact the RRZK helpdesk).

The instructions assume that you have already set up the e-mail box of your personal account in the respective e-mail client (see the instructions for setting up an e-mail client).

The use of certificates is not possible under Webmail.

If you have any questions or problems, please contact the RRZK-Helpdesk