The dkimpy-milter is a Sendmail/Postfix Milter application that signs
 and verifies DKIM (DomainKeys Identified Mail). It supports both traditional
 RSA (RFC 6376) signatures and the new ed25519 based signatures defined in
 RFC 8463.
 .
 DKIM provides a way for senders to confirm their identity when sending email
 by adding a cryptographic signature to the headers of the message.
 .
 It uses the OpenDKIM configuration option naming and definitions, for the
 options it implements, to make it easy for OpenDKIM users to experiment with
 this alternative.