DomainKeys Identified Mail: A Certain Thing
I'm amazed it's taken so long to come up with this:DKIM uses digital signatures to authenticate messages. These signatures allow you, or your e-mail service provider, to verify that a message claiming to be from your bank is really from your bank. Without authentication, if I receive an e-mail saying that my account has been compromised and requesting me to verify my personal details, it's a pretty good bet that I should ignore the message. But if I receive the same message and I can prove to my own satisfaction that it came from my bank, then I should probably pay serious attention.
DKIM can offer this proof, and it has just been published by the Internet Engineering Task Force--the group responsible for technical standards on the Internet--as an official Internet standard.