This Recommendation is one of a series defining Message Handling in a distributed open systems environment. It defines the Message Store (MS) service which supports message retrieval from the MS, and message submission through the MS in a Message Handling System. It also provides message administration services.

This edition has been revised to provide improved support in the following areas:

improved handling of authentication mechanisms when binding to the MS;

new attributes and procedures for managing multiple certificates in delivered and submitted messages;

improved handling of message tokens;

a new set of security errors;

facilities for recording the signature verification status of delivered messages;

additional matching rules;

additional attributes for correlating delivery reports.

In addition, minor errors habe been removed, Message Store procedures have been revised and extended, and numerous clarifications have been introduced.