Abstract
Nowadays email has become the most widely used means in daily communication on the net and is increasingly used in place of ordinary mail. Certified email protocols aim to provide additional properties to the standard email service. In this paper we provide a novel optimistic protocol for certified email satisfying nine of the most important properties usually considered in the literature. We give a formal description of the protocol with the Input/Output Automaton (IOA) framework and provide a prototype implementation for the Windows platform.