What is DKIM used for?

What is DKIM used for?

• A. Verifies email via DNS query with public key to verify the signature
• B. Verifies SPF
• C. Publishes DMARC policy
• D. Maps domain to IP

Answer: (A)

DKIM works by attaching a cryptographic signature to the email that can be verified using a public key published in DNS. When a receiving mail server gets the message, it fetches the domain’s public key from DNS (using a selector and the domain) and uses that key to verify the signature over selected headers and parts of the body. If the signature verifies, the recipient has evidence the message genuinely came from the claimed domain and that it hasn’t been modified in transit. This is different from SPF, which checks whether the sending server is authorized to send on behalf of the domain, or DMARC, which publishes policy about how to handle messages that fail DKIM or SPF. It also isn’t about mapping a domain to an IP—that’s what DNS A/AAAA records do.

DKIM works by attaching a cryptographic signature to the email that can be verified using a public key published in DNS. When a receiving mail server gets the message, it fetches the domain’s public key from DNS (using a selector and the domain) and uses that key to verify the signature over selected headers and parts of the body. If the signature verifies, the recipient has evidence the message genuinely came from the claimed domain and that it hasn’t been modified in transit.

This is different from SPF, which checks whether the sending server is authorized to send on behalf of the domain, or DMARC, which publishes policy about how to handle messages that fail DKIM or SPF. It also isn’t about mapping a domain to an IP—that’s what DNS A/AAAA records do.