E-mail authentication is on the rise, and much of the credit goes to Yahoo.

Yahoo came up with the idea of authenticating e-mail at the domain level, rather than with the IP address. Yahoo dubbed this concept DomainKeys and promoted it in the open source and standards communities. The IETF completed the DomainKeys Internet Mail (DKIM) standard last year, and corporate adoption is rising rapidly (Read our featured story on the rise of DKIM.)

Network World Senior Editor Carolyn Duffy Marsan interviewed Mark Risher, anti-abuse product manager for Yahoo Mail, about the benefits Yahoo is seeing from DKIM. Here are excerpts from our conversation:

How does DKIM fit in Yahoo's antiphishing strategy?

We have 260 million users; we're the largest single e-mail provider. As such, we're able to witness a broad swath of the Internet and take steps to protect our users. One of those steps was the invention of DomainKeys, which we released open source to the industry as a whole. This is a technology that we feel is needed to protect e-mail users across the Internet, not just Yahoo users. We found a lot of interest in DomainKeys both from companies sending mail on their own behalf such as PayPal as well as e-mail service providers who handle marketing campaigns for others. They all are finding some value in being able to authenticate a message back to them and to prove that the e-mail message did originate from the sender. This technology is something we felt would be very helpful for receivers so we can confer special privileges to a message. For this other message that lacks a signature, we can penalize it. We can treat it with more suspicion and run it through additional filters.

How widely is DomainKeys used?

We have seen aggressive uptake of DomainKeys. More than 40% of our inbound traffic to Yahoo Mail is using DomainKeys. That's more than 1 billion messages a day with the open source version. DKIM is its successor. We're starting to see DKIM deployed. Mail senders, both private companies and e-mail service providers, are adopting one or both technologies in parallel. These companies are starting to reach out to Yahoo to say that they are signing their messages, and they want us to start treating signed messages with special privileges or penalize messages that aren't signed. I don't have the statistic at the tip of my fingers about how much of our mail is DKIM signed, but we're seeing it rise dramatically. Within 18 months, all of the top financial institutions will use DKIM.