Email signature and encryption

1. Create a new e-mail
2. Click on the three vertical dots at the top right
3. Activate the box for Sign with SMIME
4. If you would also like to encrypt your message, also activate the ‘Encrypt with SMIME’ box.

You can now send your e-mail. Your certificate password will be requested.

When receiving the e-mail, the recipient can recognise the signing or encryption by the corresponding notes, like shown in the screenshots.

If you have problems sending encrypted emails to certain email addresses, then you are most likely missing the certificate for these addresses.

1. In the top menu, click on the dot menu (1) > Public SMIME certificates (2)
2. A new window opens
3. Check whether the recipient of your email is in this list (3). If not, you will find an email signed by the recipient and click on ‘This email is cryptographically signed. Click here to verify the signature and import the certificate.’ (Group-Office picture 5)
   If you do not have such an e-mail, ask the desired recipient to send you a signed e-mail.
4. If you do not have a certificate from your recipient or their certificate is invalid (expired, revoked), you will receive an error message. (Group-Office picture 6)

If you want to send your email encrypted to multiple addresses, you need valid certificates from all your recipients. If a single certificate is missing from the recipient list, you will receive the error message shown above. Your e-mail will not be sent.