Liam,
There is already a mechanism for encoding funny characters into a header
(it was released in the same group as the MIME RFC). This is suitable
for use in most header areas and results in a US-ASCII (7-but) string.
However it is not quite suitable for use in the *address* itself.
Especially for those people who believe the mail address should be the
same thing as the login name (there is no requirement for this, and there
are many MTA's for Unix which can support mail-name != login-name).
1342 Moore, K. Representation of Non-ASCII Text in Internet Message
Headers. 1992 June; 7 p. (Format: TXT=15846 bytes)
This encoding is =?charset?encoding?text?=
Examples
From: =?US-ASCII?Q?Keith_Moore?= <moore(_at_)cs(_dot_)utk(_dot_)edu>
To: =?ISO-8859-1?Q?Keld_J=F8rn_Simonsen?= <keld(_at_)dkuug(_dot_)dk>
CC: =?ISO-8859-1?Q?Andr=E9_?= Pirard
<PIRARD(_at_)vm1(_dot_)ulg(_dot_)ac(_dot_)be>
Subject: =?ISO-8859-1?B?SWYgeW91IGNhbiByZWFkIHRoaXMgeW8=?=
=?ISO-8859-2?B?dSB1bmRlcnN0YW5kIHRoZSBleGFtcGxlLg==?=
From: =?ISO-8859-1?Q?Olle_J=E4rnefors?=
<ojarnef(_at_)admin(_dot_)kth(_dot_)se>
To: ietf-822(_at_)dimacs(_dot_)rutgers(_dot_)edu,
ojarnef(_at_)admin(_dot_)kth(_dot_)se
Subject: Time for ISO 10646?
To: Dave Crocker <dcrocker(_at_)mordor(_dot_)stanford(_dot_)edu>
Cc: ietf-822(_at_)dimacs(_dot_)rutgers(_dot_)edu, paf(_at_)comsol(_dot_)se
From: =?ISO-8859-1?Q?Patrik_F=E4ltstr=F6m?=
<paf(_at_)nada(_dot_)kth(_dot_)se>
Subject: Re: RFC-HDR care and feeding
And, yes, these are pretty unreadable in ASCII. The users UA will need
to be able to translate in/out of this (and any other) encoding in use.
While this encoding *could* be used in an address (that is:
To: =?ISO-8859-1?Q?Andr=E9_?= Pirard
<"=?ISO-8859-1?Q?Andr=E9_?="@vm1.ulg.ac.be>
is legal RFC-822) there are MTA's for which this will break. For
instance MMDF uses `=' to provide extra addressing.
Because some MTA's have known interpretations of the local part
what is being debated is the form of a different encoding system.
All of which was covered in discussion some weeks ago. But it sounded
as if you weren't aware of all this. If I am mistaken, please forgive me.
David