Sign email messages
- Access Outlook configurations by selecting the File option on the menu located in the top left corner.
- Select Options.
- Select the option Trust Center and then click on Trust Center Settings.
- In the new interface, please select the Email Security option and then click on Settings. If you would like to have all your emails digitally signed by default, please select Add digital signature to outgoing messages. You can send digitally signed emails without them being encrypted by selecting the option Send clear text signed message when sending signed messages.
- In the section Certificates and Algorithms, namely Signing Certificate, click on Choose.
- Select your Digital Certificate and click on OK.
- Once your Digital Certificate is selected, make sure that the option SHA256 or above is selected in Hash Algorithm.
- Click on OK to continue.
- NOn the Default Setting of the Email Security interface, there should appear My S/MIME Settings ([email protected]*.up.pt).
- Click on OK to complete the configuration.
- As soon as this configuration is completed, messages sent through Microsoft Outlook will be digitally signed by default.
- On the first use, you should allow Microsoft Outlook to access your Private Key. This option might be requested at certain times.
- Click on Allow.
- The digital signature ensures that the messages are from the identified sender without a doubt.
- Message in the Inbox.
- Message after opening.
- If you only wish to sign messages once in a while, you should disable the option Add digital signature to outgoing messages.
In this case, to digitally sign a specific message in Microsoft Outlook, you should click on the Sign icon on the Options menu, located on the top bar.