DomainKeys Identified Mail (DKIM) is an email security standard that protects your domain name from email spoofing, ensures emails are not altered during transit, and prevents outgoing emails from getting marked as spam.
How DKIM Works
DKIM creates and attaches a digital signature to every outgoing email, which receiving servers use to verify that the message is authentic and has not been altered in transit.
The process involves cryptographic keys: DKIM generates two keys—a private key and a public key. The private key is kept on the outgoing email server and provides a signature for outgoing emails. The public key is kept on the DNS server, and Internet Service Providers (ISPs) can access it when they receive a DKIM-signed email. If the keys match, the email is considered authentic and is delivered to the inbox.
DKIM and Email Authentication
SPF, DKIM, and DMARC work together to authenticate and deliver emails. These three protocols create a multi-layered security approach that protects against email spoofing and phishing attacks.
DKIM specifically addresses the integrity of email messages in transit, while SPF verifies the sending server and DMARC ties the two together with a reporting and policy enforcement mechanism.
Limitations of DKIM
While DKIM is an important email security standard, it does not protect against all forms of email attack. DKIM does not prevent attackers from sending emails from lookalike domains or from using compromised legitimate accounts to send malicious messages. For comprehensive email security, DKIM should be used in conjunction with SPF, DMARC, and advanced email security solutions.