E-mail sig­natur: Outlook

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

Valid sig­na­ture

In Microsoft Out­look, dig­i­tally signed e-mails dis­play the note «Signed By» and a small seal icon in their header.

The ver­i­fied sender of a signed e-mail is def­i­nitely the signer of this mail. You should there­fore take note of the line «Signed By» 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 Microsoft Out­look estab­lishes any prob­lems when checking a dig­ital sig­na­ture, a note to this effect is dis­played in the «Signed By» line. By clicking the button at the end of this line, you can then 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.