How do I identify signed emails?

Depending on the software you use to read your mails, a (valid) signature is displayed on the mail in different ways. Sometimes the issuer of the certificate is also displayed. Depending on the software and the date of issue of the certificate, the publisher's names are 'Universitaet Kiel' (until 2016) and 'Christian-Albrechts-Universitaet zu Kiel' (from 2016) or 'Verein zur Foerderung eines Deutschen Forschungsnetzes e.V.'. (from 2018) or also 'Uni Kiel CA - G02'.


Outlook displays the signature by a small red seal icon next to the mail. Please note: Outlook does not check whether the sender of the mail is consistent with the person signing the mail (or their mail address), but simply shows you both pieces of information:

Signierte Mail in Outlook


Thunderbird will display a sealed envelope for correctly signed mails. By clicking on this seal you can get more information about the certificate (e.g. the issuer):

Signierte Mail im Thunderbird

Webmailer Roundcube

Roundcube shows correctly signed mails by a large green bar above the text that names the signing person and issuer of the certificate:

Gültiges Mailzertifikat im Roundcube

'Wrong' signatures (e.g. if the sender name does not match the name of the signature) are indicated by a red bar.