This document specifies a secured electronic postal service, referred to as the Electronic Postal Certification Mark (EPCM) service, which provides a chain of evidence, stored by an administration as a trusted third party, to prove the existence of an electronic event, for a certain content, at a certain date and time, and involving one or more identified parties.The service is defined by reference to the concepts, schemas and operations defined in CEN/TS 15121-1, Postal Services - Hybrid Mail - Part 1: Secured electronic postal services (SePS) interface specification - Concepts, schemas and operations. It requires support for five core SePS operations and