How to Configure an email (S/MIME) certificate on Outlook 2003

August 16, 2019 in Windows and Email S MIME

Note: If you previously applied for your certificate using Internet Explorer on the same computer as your Outlook installation then it should already be installed.

You can skip straight to 'Signing and Encrypting'.

Note: If you previously used Firefox to collect your certificate, then you will need to export the certificate from the original browser which was collected in a PFX/P12 format.
Note: If your certificate resides on a different machine, you need to transfer it to the computer where Outlook is installed.

- email it to yourself or save the certificate file to USB then copy it over.
- Then follow the 'import' instructions in this document.

Importing your certificate into Outlook 2003

Signing and Encrypting mails

Importing your Certificate into Outlook 2003:

  1. Open Outlook 2003, then click Tools > Options...

  2. In the Options screen, click Security > Import/Export...

  3. In the Import/Export Digital ID interface, navigate to the location of your PKCS12 certificate file and click Open.

    Enter the password that was used while exporting the certificate and provide a Digital ID name.

  4. Click OK

  5. Select the security level for storing the Private Key in your system and click OK

  6. Click Apply and then OK in the Options screen

That's it. You have successfully imported your Sectigo Personal Authentication certificate into Outlook 2003.

Signing and Encrypting Mails

  • Signing an email ensures the recipient knows the email has come from you and informs them that it has not been modified in transit.

  • Encrypting an email ensures that only the recipient can read the email content and attachments.

Note: In order to encrypt email, you must first have your recipient's email certificate in your certificate store. To obtain their certificate, you need to get your contact to send you a signed email. Upon receipt of the signed email, their certificate will be automatically imported into your certificate store and you will be able to sign/encrypt email to that person.

Assign the certificate

  1. Open Outlook 2003, then click Tools > Options...

  2. In the Options screen, click Security > Settings..

    The Change Security Settings dialog allows you to choose signing and encryption certificates. In most cases you should be using your Sectigo Personal Authentication Certificate for both signing and encrypting.

    User-added image
  3. Click the 'Choose' button next to the Signing Certificate field.

    - A new window will appear which will allow you to choose your signing certificate from the list of imported certificates.

  4. Choose your Sectigo Personal Authentication certificate and click OK

    - If you are unsure, you can highlight a certificate and click the View Certificate button to see certificate details.

  5. Repeat the process for the 'Encryption Certificate', again choosing your Sectigo certificate.

    - When you return to the Change Security Settings window, you will see your certificate listed as the signing and/or encryption certificate fields

  6. Click OK to return to the Options screen.

  7. Click Apply and then OK in the Options screen.

Signing and encrypting individual mails

  • To sign or encrypt an individual mail, first compose a new mail or reply to/forward an existing mail.

  • Click Options... on the message tool bar and in the Message Options screen,
    Click the Security Settings button and then select the Encrypt message contents and attachments and / or Add digital signature to this message check boxes depending on your requirements in the Security Properties screen and click OK.
    Alternatively, click one or both of the Sign and 'Encrypt' buttons.

    Note: If the Sign and Encrypt icons are not available in the tool bar, you can place them using the Toolbar Options button next to Options...

When the email is sent, it will be signed and/or encrypted per the options selected.

Signing and encrypting all mails by default

  1. Open Outlook 2003, then click Tools > Options...

  2. In the Options screen, click the Security tab

    • To encrypt every message by default, check the Encrypt contents and attachments for outgoing messages box

    • To sign every message by default, check the Add digital signature to outgoing messages box

    • Leave one or both of these check-boxes unchecked if you only wish to encrypt/sign messages on an individual basis.

    • As a rule of thumb, many users choose to digitally sign by default but only encrypt when sending a message which requires confidentiality.

  3. Click Apply and OK