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From: Dan Hoey <hoey@NRL-AIC.ARPA>
Newsgroups: net.mail.headers
Subject: Re: RFC 934 - Message Encapsulation
Message-ID: <8250@brl-tgr.ARPA>
Date: Mon, 11-Feb-85 19:29:55 EST
Article-I.D.: brl-tgr.8250
Posted: Mon Feb 11 19:29:55 1985
Date-Received: Fri, 15-Feb-85 04:12:35 EST
Sender: news@brl-tgr.ARPA
Organization: Ballistic Research Lab
Lines: 39

Marshall,

I am surprised that you say

    ... we need to bit (well, byte) stuff.  This is the ONLY
    way to unambiguously separate messages in a digest (or a forwarding of
    messages, in general).

I have previously indicated to you that there is a way to entirely
avoid modification of the text of messages.

Header People,

The method I proposed was for the Forwarding Agent to choose an
encapsulation boundary that does not occur in the messages to be
encapsulated.  Barry Margolin's proposal of indicating the chosen EB in
the header is an appropriate way of communicating the choice to the
Bursting Agent.  However, the use of this boundary followed by a space
for stuffing is not necessary.

An algorithm for choosing the EB:

    1.  Form a list of trial EB's.  I suggest the trial EB's be
	- twenty hyphens,
	- twenty hyphens followed by the current date and time, and
	- twenty hyphens followed by twenty randomly-chosen
		alphanumeric characters.

    2.  Scan the messages to be encapsulated for occurrences of the trial
        EB's.

    3.  If all of the trial EB's were found, fail.  (If messages are
	being encapsulated at a rate of a megabyte per second, this step
	should be taken fewer than once every quintillion centuries,
	barring hardware failure.)

    4.  Return the first of the trial EB's not found in any message.

Dan