E-mail fraud is a global problem that plagues consumers and businesses, costing millions of dollars in direct losses, technology expenditures, lost productivity and network downtime. With phishing attacks on the rise, leading companies are working to develop e-mail authentication protocols that protect users from e-mail fraud.

DomainKeys Identified Mail (DKIM) is an e-mail authentication proposal that strengthens user protection from e-mail forgery, and increases accountability for spam and phishing scams. DKIM defines a domain-level authentication framework for e-mail using public key cryptography and key server technology to permit verification of the source and contents of messages by mail transport agents or mail user agents. The goal of this framework is to prove and protect message sender identity and the integrity of the messages they convey, while retaining the functionality of Internet e-mail as it's known today.

The specification merges Yahoo's DomainKeys and Cisco's Internet Identified Mail e-mail verification technologies, which have similar attributes. Cisco and Yahoo submitted the combined technology to IETF last month for consideration as an e-mail industry standard and to help enable industry-wide adoption of the technology.

DKIM uses public key cryptography to let users verify and maintain message integrity, and identifies legitimate messages. The proposed standard uses DNS in the same manner as DomainKeys, Yahoo's anti-spam protocol, which is in use around the world. DKIM also leverages Cisco's Internet Identified Mail header-signing technology, ensuring signature consistency as messages are sent through networks.

Big benefits

 

The benefits of signing e-mail using DKIM can be substantial for banks, utilities, e-mail commerce services and other companies that send transactional e-mail to consumers. Providing customers with a means to detect fraudulent e-mail can translate directly into increased user satisfaction, reduced customer care costs and strengthened brand reputation.

To sign an e-mail with DKIM, an e-mail administrator first creates one or more public/private key pairs using free software. The public portions are put into the domain's DNS records, while the private portions are given to the domain's sending mail servers. When sending a message, the mail servers use a private key to create a digital signature covering the message's headers and body, which is inserted in the headers.

When the recipient's e-mail system receives a DKIM message, it performs a DNS lookup to retrieve the domain's public key. With the public key and the message contents, the server can verify that the digital signature is valid, thus proving that the message was signed by an authorized party, meaning it is not a forgery. If the recipient's e-mail system receives a message that does not contain a DKIM signature, it performs a DNS lookup to determine if the domain indicates how much of its e-mail is signed. If it indicates that all messages are signed, the recipient can be certain that the message is not authentic.