The present disclosure provides a system and method for certifying the delivery of electronic mail messages. In one embodiment, the sender contacts a proof-of-delivery-request creation server which receives the message the sender would like to obtain a proof-of-delivery for, generates a processed message and a proof-of-delivery-request, and returns both to the sender. The sender then uses his regular email infrastructure to transmit to the recipient the processed message and the proof-of-delivery-request as a single email. Upon receiving the sender's email, the recipient contacts a proof-of-delivery-request processing server operated by a trusted-third-party and sends it the proof-of-delivery-request. Said server processes the proof-of-delivery-request, notifies the sender that the recipient has received the message and provides the recipient with information usable for extracting the original message from the processed message.