An optimistic certified e-mail protocol for the current Internet e-mail architecture

Certified mail is a service where an item is delivered to the recipient in exchange of an evidence as proof he has received this item. Therefore certified e-mail should be a service where an e-mail is delivered to its recipient in exchange of evidence proving the recipient has received this e-mail. Even though there are several scientific proposals for certified e-mail (ce-mail), the only real applications we can find offering ce-mail services come from private companies or the public administration. All of them are designed with independence of traditional e-mail infrastructures, tailored to custom needs (private companies and administration) and do not address interoperability between different systems. This explains why scientific proposals have not reach the implementation phase and why existent proposals are not widespread. In this paper we present a ce-mail solution designed taking into account the existent Internet e-mail infrastructure, providing all the required evidence about the submission and the receipt of certified e-mails.