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Email complianceReviewed September 7, 2026

What is DKIM?

DKIM associates a signing domain with a message and cryptographically validates that claim of responsibility.

Who this applies to#

  • DKIM signing may be performed by an author organization, relay, or agent

What DKIM requires#

  • RSA DKIM must not use rsa-sha1 and signing keys must be at least 1024 bits

What this does not require#

  • DKIM does not prove the identity of the human author

Common mistakes#

  1. Treating the signing domain as proof of the human author

DKIM checklist#

  • Identify the signing domain
  • Use permitted cryptography
  • Check alignment for receiving policies

Commonly confused with#

OnVoard's take#

DKIM is strongest when its signing identity is understood alongside the visible From domain.

Official sources#