SMTPSMIMESign

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

Set to N (no) to disable digital signatures for outbound emails, or Y (yes) to turn them on. The default is N.

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

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