Yahoo Breaks Out Crypto App For Its E-Mail ServiceYahoo Breaks Out Crypto App For Its E-Mail Service

In the escalating war on spam, Yahoo says it's incorporating cryptographic authentication software into its Yahoo Mail service.

DomainKeys, as the software is called, is designed to protect customers against the kind of spam that is used for phishing attacks and identity fraud by posing as a message from a trusted entity.

"Authentication is really the first step in the spam fight we've been waging," says David Maynes, a principal engineer at the ISP EarthLink, which will test DomainKeys. "It's about getting some accountability back into the mailstream."

If it's indeed appropriate to talk about spam in terms of war, then it's a world war. The number of countries sending spam rose to 171 in October, up from 166 the month before, according to anti-spam software maker Commtouch Software. That leaves just 21 of the 192 countries recognized by the United States on the sidelines.

DomainKeys is considered one of the two leading applications for E-mail authentication. The other is Microsoft's Sender ID, a combination of its earlier Caller ID for E-mail proposal and the Sender Policy Framework, developed by Meng Wong, co-founder and chief technology officer of Pobox.com.

Sender ID recently had a near-death experience when it was rejected by open-source advocates and America Online. They subsequently embraced the proposal after Microsoft made some changes to Sender ID's specification.

Sender ID uses Sender Policy Framework records, published by mail senders, as a way to determine whether a message actually comes from the domain listed in the message header. DomainKeys validates messages cryptographically to ensure that the message header and message body have not been forged.

According to Maynes, there's some overlap in the two technologies, but they do complement each other.

"It appears that the heavy-weight crypto solutions are coming on line faster than anticipated," says Dave Lewis, VP of deliverability management for online-marketing firm Digital Impact, who considers authentication technology crucial as a means to restore confidence in E-mail as a marketing medium.

In a letter to the U.S. Federal Trade Commission, which held a summit on E-mail authentication last week, David Rossetti, VP of strategic software technology at Cisco Systems, detailed the benefits of the technology.

"Authentication systems will result in cost savings and efficiency benefits for users, including increased productivity and reduction of storage and filtering requirements," Rossetti wrote. "Identification of the sender also serves as a foundation on which existing and future accreditation and reputation services may be based."

Both Lewis and Rossetti suggest that reputation services will become more important once authentication becomes possible. The reason is that there's value not only in knowing who sent a message but in whether the sender is trustworthy.

Never more so, now that spammers have turned to vast networks of zombie PCs to get their messages past IP-based and content-based filters. These machines, the source of an estimated 70% of the world's spam today, have been compromised by worms, viruses, or spyware such that they can be controlled by a remote hacker.

Vendors selling reputation-based services include IronPort Systems, Cloudmark, Goodmail Systems, and Habeas. IronPort appears to be well-positioned to benefit from the supposed synergy between authentication and reputation.

The company has upgraded its Reputation Filters to allow ISPs to stop spam that originates from within a network. Typically, such spam comes from subverted PCs. IronPort also says the ISP Charter Communications has chosen IronPort's C-60 E-mail security appliance to protect its 1.8 million customers.

Pete Schlampp, senior director of product marketing at IronPort, says that reputation filtering saves customers from having to purchase more hardware to handle the ever-increasing volume of spam. It does so by blocking as much as 70% of spam before it needs to go through computationally intensive content-based filtering.

For spammers, the response may just be to send even more mail to compensate.