DomainKeys Identified Mail (DKIM) is one of the tools Yahoo! uses to fight against forged email. It uses encryption The conversion of data into a form that cannot be easily understoodtechnology to verify that an email is really from the domain A domain name locates an organization or other entity on the internet. Examples: yahoo.com and wikipedia.org from which it appears to be. If a message has been verified through DKIM, you'll see a small icon of an envelope and key in the email header (in Mail Classic only).

It's also a good idea to manually double-check the From: field of an email message to make sure it is really from who it claims to be from. For example, an email from Yahoo! is from "...@yahoo.com" and not from a spoof domain such as "...@y9ho00oo.com".

For more information about our tools and how you can protect yourself from forged email, visit our Anti-Spam Center.

If you're a postmaster The person who administers email for a domaininterested in having your site implement DomainKeys to protect your domain, you can find details here. If you are an end user of an email domain that you want to have use DKIM, contact the postmaster for your domain by sending an email to "postmaster" at your domain (for example, postmaster@[yourdomainname].com).