What is Domainkeys?
DomainKeys is a technology proposal that gives email providers a mechanism for verifying both the domain of each email sender and the integrity of the messages sent (i.e. that they were not altered during transit). By signing its messages, a domain can on the one hand take responsibility for what it sends, and on the other hand, explicitly define its policy as regards unsigned messages claiming to come from that domain. DomainKeys, as such, provides a way for a domain to protect its identity.