This approach uses public key cryptography to allow users to verify and maintain message integrity, and identifies legitimate messages.
DKIM uses the Internet's Domain Name System (DNS) in the same manner as DomainKeys. DKIM also leverages Identified Internet Mail's header-signing technology, ensuring signature consistency as messages are sent through the network.
The benefits of signing e-mail using DKIM can be significant for companies that commonly send transactional e-mail to consumers, such as banks, utilities, and e-commerce services.
Yahoo has developed and implemented DomainKeys technology in an effort to address the growing threat of e-mail forgery. DomainKeys leverages public-key cryptography to verify the sender of an e-mail message at the domain level. A sending system uses a private key to generate a signature and inserts the signature in the e-mail header; and the receiving e-mail system uses the public key, published in the Internet's Domain Name System, to verify the signature of the e-mail.