XgenPlusXgenPlusHelp Center

Digitally sign a mail with S/MIME

To sign a mail with S/MIME, open new compose and click the shield icon. Turn on Digitally sign and send as usual. Recipients can then verify that the mail came from you and was not altered. You need an active S/MIME certificate first, which you generate in Settings › Security › S/MIME Certificates.

For: EveryoneWebAndroidSecurity

How to digitally sign a mail with s/mime

  1. Make sure you have an active certificate in Settings › Security › S/MIME Certificates.
  2. Click Compose Mail to open new compose.
  3. Click the shield icon and turn on Digitally sign.
  4. Check that the status reads "Message will be digitally signed."
  5. Write the mail and click Send.

When to use it

Geeta, a government officer, signs a tender clarification with her department-issued certificate. Bidders can confirm that it came from her office and was not changed.

Good to know

  • When you reply to a signed S/MIME mail, the original signature is kept with the quoted message.
  • To also hide the content from everyone but the recipients, turn on Encrypt for recipients.

Common questions

Can people outside my organisation check the signature?

Yes. S/MIME is a standard that Outlook, Apple Mail and Thunderbird understand. They may need your organisation's CA certificate to show the sender as trusted.

Why is the delivery report option unavailable?

XgenPlus turns off delivery reports while S/MIME is selected, to keep the protected mail confidential.

For admins

Administrators control this feature for the whole domain:
Was this page helpful? Updated 2026-10-28