DKIM, ARC and TLSRPT email signing and verification
dkimpy is a library that implements DKIM ARC and TLSRPT email signing
and verification.
DKIM (DomainKeys Identified Mail)
ARC (Authenticated Receive Chain)
TLSRPT (TLS Report)

Basic DKIM requirements are defined in RFC 6376:
https://tools.ietf.org/html/rfc6376