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 permits optional support seven others.This version of the specification does not cover: a description of the issues surrounding inter-operability between multiple postal SePS implementations when a business transaction Lifecycle requires the participation of more than one SePS implementation in a cross-border scenario involving two or more postal services; issues surrounding SePS usage in a `multiple Certificate Authority' scenario where inter-operating posts are participating in a cross-border transaction as described above; examination of "Certificate Authority deployment model" alternatives necessitated by the cross-border scenarios described above.