SMTPSMIMEEncryption

Use this to specify whether to encrypt outbound emails using the Secure/Multipurpose Internet Mail Extensions (S/MIME) format.

Set to N (no) to disable encrypted outbound emails, or Y (yes) to turn on S/MIME encryption. The default is N.

See MultiChannel Framework: Configuring Signed and Encrypted Emails for additional configuration required for encrypted outbound emails.

You can override the setting using PeopleCode. See PeopleCode API Reference: SMIMEEncryption property: MCFEmail class.