Patent ID: 7194515

Claim:
A method of operating a computer for the purpose of validating e-mail messages to enable blocking of unwanted ones of said e-mail messages, said method comprising the steps of: preparing, in response to the receipt of a predetermined e-mail message, a data key encoding information reflective of some aspect of said predetermined e-mail message; issuing a challenge e-mail message including said data key; detecting whether a response e-mail message, responsive to said challenge e-mail message, is received and whether said response e-mail message includes a response key encoding predetermined information reflective of a predetermined aspect of said challenge e-mail message; recording, in response to receipt of said response key, a source address in a verified source address list; and accepting receipt of said predetermined e-mail message on condition that the source address is recorded in said verified source address list and alternatively on condition that said predetermined e-mail message includes said response key.