DKIM
DomainKeys Identified Mail
A cryptographic email signing standard that lets receiving servers verify a message was actually sent from the claimed domain and was not modified in transit.
DKIM (DomainKeys Identified Mail) uses public-key cryptography to sign outbound mail. The sending mail server signs each message with a private key; the corresponding public key is published in DNS. Receiving mail servers fetch the public key, verify the signature, and confirm the message was sent by an authorized server for that domain and was not altered in transit. DKIM is standardized in RFC 6376. DKIM alignment with the From: header domain is a required component of DMARC enforcement. Rotated keys, key length below 1024 bits, and unsigned mail-authentication headers all weaken DKIM protection.
A domain without DKIM, or with weak DKIM keys, cannot enforce DMARC. Advisor tenants (CPA, attorney, wealth manager) that lack DKIM are one email spoof away from a wire-fraud pretext landing in the principal inbox. LeakTrace evaluates DKIM alongside SPF and DMARC as part of the wire-fraud precursor surveillance layer.