A method and system for verifying identification of an electronic mail message. An electronic mail message including a signature and a key is received, the signature identifying a domain from which the electronic mail message originated and the key for verifying the signature. A key registration server of the domain is accessed to verify the key. The key registration server provides for verifying that a key used to sign an electronic mail message is valid and that the sender is authorized by the domain to send the electronic mail message from the return address.