How do I recognise a digitally signed email?

In Outlook, you can recognise a validly signed email by the signature button ("emblem wreath") in the top right-hand corner of the message window. A line of text on the left-hand side indicates who signed the mail.

Click on the signature button ("emblem wreath") to open a window with an explanation of the signature.

Click on "Details..." to display further information on the signature used.

Click on the "Signer: ..." line and click on the "Show details..." button to obtain further information on the signature and the certificate used.

Click on the "Display certificate ..." button to display the certificate.

You can also recognise an invalidly signed email by the signature button in the top right-hand corner of the window. In this case, a yellow triangle with a red call sign is used as the symbol. A line of text on the left-hand side indicates that problems with the signature have been recognised. The mail header and the message are also separated by a red line.

Here too, clicking on the signature button (yellow triangle) opens a new window with further explanations.

In Thunderbird, you can recognise a validly signed email by the signature button ("S/MIME" lettering and laurel wreath) in the top right-hand corner of the window.

Clicking on the signature button ("S/MIME" lettering and laurel wreath) opens a window with explanations of the signature.

Click on "View signature certificate" to display further details on the certificate used.

You can also recognise an invalidly signed email by the signature button in the top right-hand corner of the window. In this case, the signature button again consists of the word "S/MIME" and a laurel wreath, which is displayed at the bottom right with a red triangle with a white exclamation mark above it.

Here too, a click on the signature button opens a new window with further explanations.