The basic purpose of 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 retrieval, etc. of e-mails sent/delivered through such service. The present document specifies an architectural structure of REM, more specifically: 
a) describes a logical model for REM including the most relevant REM architectural elements and how they relate to each other (REM-MD Messages, REM Sender, REM Recipient, etc.) and the following styles of 
operation: 
1) "Store and Forward" (S&F henceforth), whereREM Objects are directly forwarded from REM-MDs to the REM Recipient; and 
2) "Store and Notify" (S&N henceforth) where the REM Recipient is first notified of that a REM Object is stored and is provided with a reference to the location where the REM Object can be downloaded. 
b) describes how REM components interact using external interfaces to REM users, and interfaces to other REM implementations; 
c) describes a policy domain environment; and  
d) specifies a list of different types of events and the REM-MD Evidence types that represent them.