Home Page Navigation Contents Contact Sitemap Search

E-mail signatur: Thunderbird

These instructions will show you how to check a digital e-mail signature in Thunderbird.

Valid signature

In Thunderbird, digitally signed e-mails show an envelope with a seal in their headers.

The verified sender of a signed e-mail is definitely the signer of this mail. Click on the sign to obtain secure sender information, i. e. to establish the signer of a mail. The sender stated in the header of the e-mail does not belong to the protected area of the e-mail and can therefore be faked.

Invalid signature

In case Thunderbird establishes any problems when checking the digital signature, a sign with a «!» is displayed in the header of the e-mail. By clicking this sign, you can obtain further information on the error found.

Problems with signature verification can be due to the following: The sender certificate is invalid (i. e. expired, declared invalid or faked), or the contents of the e-mail were changed on their way to the recipient (either accidentally or deliberately). If there are problems with a signature, please contact the message sender.

E-mails can be signed just like any physical document. The counterpart for handwritten signatures in this case is called a «digital signature». Signed e-mails unequivocally confirm the authorship of an e-mail, i.e. they cannot be faked and guarantee the integrity of the contents of an e-mail.

What else would you like to learn about security when e-banking?

Register for a course now
and learn more:

Online basic course

Find out about current Internet threats and some easy protective measures, and how to securely use e-banking.

further information

Online course mobile banking/payments

Find out about mobile banking, mobile payments and how to securely use these apps.

further information

Online course for the under-30s

Learn how to use your smartphone securely. Next to basics, we will show you what you should know about social media, clouds, mobile banking and mobile payments.

further information

Online course for SMEs

Is your organisation sufficiently secure? Learn which measures you can take to significantly strengthen your organisation’s IT security.

further information