Learn how to use encryption and other security settings to protect messages sent from Outlook.

Send S/MIME or Microsoft Purview encrypted emails in Outlook using a work or school account with a qualified Microsoft 365 subscription.

If you have a Microsoft 365 Family or Microsoft 365 Personal subscription, Outlook includes encryption features that let you share your confidential and personal information while ensuring that your email …

Before you can send and receive messages with encryption or digital signatures, or digital IDs, please follow the instructions to set up encryption in Outlook. Note: To use encryption, your account must …

Learn how to identify and open encrypted and protected emails no matter what email client you're using.

Under Microsoft Outlook Trust Center, select Trust Center Settings. On the Email Security tab, under Encrypted Mail, select the Add digital signature to outgoing messages check box.

Learn how to use digital signatures and encryption in Outlook for Mac. Both the sender and recipient must have a mail application that supports the S/MIME standard.

Outlook uses certificates in cryptographic email messaging to help keep communications secure. You can view your own certificates or those that you receive in email messages.

To apply IRM protection, S/MIME signature and encryption must be removed from the message. The same applies for IRM-protected messages; users can't sign or encrypt them by using S/MIME.

Once you exchange signed mail and install the certificate, you will be able to send encrypted emails. If you can't encrypt, you are missing the recipient's public key.