DomainKeys is an email authentication system developed to help verify the authenticity of email messages and prevent email spoofing, phishing, and spam. It works by using cryptographic signatures to confirm the identity of the sending domain and ensure the integrity of email content during transmission.
Key aspects of DomainKeys include:
- Digital Signatures: DomainKeys uses cryptographic signing to apply a digital signature to outgoing emails. This signature is generated using a private key unique to the sending domain.
- Public Key Retrieval: The public key corresponding to the private key used for signing is published in the Domain Name System (DNS) records of the sending domain. This allows receiving email servers to retrieve the public key when verifying the authenticity of incoming emails.
- Signature Verification: When an email is received, the receiving email server retrieves the sender’s public key from the DNS and uses it to verify the digital signature attached to the email. This verification process ensures that the email has not been tampered with during transit and originates from the claimed domain.
- Header Information: DomainKeys typically adds a header to the email message containing the cryptographic signature and information related to the signing domain. This header helps receiving mail servers verify the authenticity of the email.