certificate installation

  1. In Thunderbird, open "Account Settings" and select "S/MIME Security" under the appropriate email account. Figure 1.1: Mozilla Thunderbird
  2. Under the section Certificates select the button "Manage Certificates...", then switch to the selection "Your certificates" and click on "Import".
  3. Now select the previously saved certificate and enter the password. The certificate is now imported.
  4. Back to the previous window (S/MIME Security), here you can now select the just imported certificate under "Digital Signature" and under "Encryption".
  5. Now check the options "Sign messages digitally" and "Required ..." under Encryption and confirm with "OK".
  6. If you now write a new mail, there is an S/MIME button in the toolbar where you can choose separately per mail whether it is encrypted and/or signed. Figure 1.2: Mozilla Thunderbird
  7. If you receive an S/MIME mail, Thunderbird shows this via a lock icon: Figure 1.3: Mozilla Thunderbird

Address book integration with Thunderbird eliminates the need to request a signed email in advance from the recipient of an encrypted email.

Learn more about address book integration.

  1. Open Outlook and select "Options" under "File".
  2. Here you select the "Trust Center" section on the left-hand side and click on the "Settings for the Trust Center..." button See: Figure 1.1: Outlook
  3. In the window that now opens, select the "E-Mail Security" section on the left side: Figure 1.2: Outlook
  4. In the right section of the "Digital IDs (Certificates)" area, please select "Import/Export", in the window that now opens go to "Browse", select the corresponding certificate and confirm it with "OK".
  5. You will now return to the "Import/export digital ID" view. There, please enter the password that you have assigned during the export process. Then give the certificate a name and confirm with "OK": Figure 1.3: Outlook
  6. Now your certificate has been imported into Outlook and you can set it for the email address in the "Encrypted email messages" section via the "Settings" button: Figure 1.4: Outlook
  7. Now you should see under "Signature Certificate" and "Encryption Certificate" the certificate that you have just installed. If this is not the case, you still have to select the certificate by clicking the "Select" button. Figure 1.5: Outlook
  8. By pressing the "OK" button the setup is completed.
  9. It is recommended that you restart Outlook after this procedure.
  10. If you now write a new mail, you can choose separately for each email whether it should be encrypted and/or signed: Figure 1.6: Outlook
  11. If you receive an S/MIME-mail, Outlook shows this via the following icons: Figure 1.7: Outlook

  1. Import the certificate into Keychain Management by double-clicking the certificate file you received from the certification authority.
  2. After your certificate is imported, it should appear in the "My Certificates" category in Keychain Management.
  3. Open your certificate in Keychain Management and make sure that the setting "Use system defaults" or "Always trust" is checked. You can now use the certificate to send and receive signed and encrypted emails. The installation is now complete.
  4. If the certificate cannot be imported in the described way, you can try moving the file to the keychain management icon in the Finder.
  5. To use S/MIME, Apple Mail must be restarted. 
  6. For testing it is recommended to send yourself an encrypted mail.
  7. If you enter a recipient address that supports S/MIME, two new buttons now appear in the email window: Figure 1.1: Apple. The right button signs a mail, the left one encrypts it.
  8. If you receive such a mail, there will be a new line, which shows if everything is ok: Figure 1.2: Apple. Here you can see that the mail has been encrypted and signed.
    The text of the mail is automatically displayed unencrypted. So except for this line you don't notice that you are working with encrypted mails. If an error occurred, e.g. the certificate could not be verified, Mail will show this in a clear message.

Further information:

https://support.apple.com/en-gb/guide/mail/mlhlp1179/mac, opens an external URL in a new window

https://support.apple.com/en-gb/guide/mail/mlhlp1180/mac, opens an external URL in a new window

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