Mail) sender authentication system proposed by the E-mail Signing Technology
Group (ESTG), now standardized by the IETF (RFC4871). It also includes
implementations of the Author Domain Signing Practises (ADSP, RFC5617) and
Vouch By Reference (VBR, RFC5518) proposed standards.
The project started from a code fork of version 2.8.3 of the open source
dkim-milter package developed and maintained by Sendmail, Inc.
