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.