How does DKIM work?

• Key Generation: A sender creates a cryptographic key pair: a private key and a public key.
• Private Key Encryption: The private key is used to encrypt a hash of the email’s content (including headers and body).
• Public Key Storage: The public key is published in the sender’s DNS (Domain Name System) records.
• Signature Creation: The encrypted hash (the DKIM signature) is added to the email’s header.
• Verification: When the recipient’s email server receives the email, it retrieves the public key from the sender’s DNS record.
• Hash Comparison: The server uses the public key to decrypt the DKIM signature and recomputes a hash of the email’s content.
• Authentication: If the decrypted hash matches the recomputed hash, it confirms that the email’s content hasn’t been altered since it was signed by the sender, and the email passes the DKIM check.
• Improved Deliverability: DKIM, along with other authentication methods like SPF and DMARC, helps improve email deliverability and reduces the likelihood of emails being marked as spam.