ETSI TS 102 640-2 V2.2.1 (2011-09) - Electronic Signatures and Infrastructures (ESI); Registered Electronic Mail (REM): Part 2: Data requirements, Formats and Signatures for REM

The basic purpose of a Registered E-Mail service is to provide users, in addition to the usual services supplied by the ordinary e-mail service providers, with a set of evidence suitable to uphold assertions of 
acceptance (i.e. of "shipment"), of delivery/non delivery, of receipt, etc. of e-mails sent/delivered through such service. 
The present document provides:  
a) Rules for building a REM-MD Envelope and, consequently, a REM Dispatch or a REM-MD Message. 
b) Syntax and semantics of REM-MD Evidence to be produced by a REM Management Domain. 
c) Rules on the signature to be used within REM-MD Envelopes. 
REM-MD Evidence formats are deemed to comply with legal, regulatory or contractual requirements to provide legal validity and enforceability under domestic or international law.