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Re: [ietf-smtp] quoted-unprintable ?

2021-03-21 14:29:44
"John Levine" <johnl(_at_)taugh(_dot_)com> writes:

The advantage of BINARYMIME over base64 is that base64 is 33% bigger
since it encodes six bits per octet rather than 8.  It occurs to me that
since everone these days supports 8BITMIME, one could invent a
quoted-unprintable encoding that encodes only the characters that are
special, CR LF NUL.  (To play it safe I'd also encode 0xff).  This gets
you about a 2% size increase and stays compatible with 8BITMIME.

This seems totally obvious.  Has anyone proposed it before?

Yes, on Usenet, and it looks like the authors also thought of using it on
email as well.  It's called yEnc:

I don't think there was ever an RFC, though.  The deployment on Usenet was
very YOLO and at least at the start openly eschewed MIME in favor of using
it similar to uuencode, which made me leery of it.  I'm not sure if that
was subsequently fixed because I lost track of further developments since
I didn't care much about binary Usenet and the author didn't participate
in standardization discussions very much.

Russ Allbery (eagle(_at_)eyrie(_dot_)org)             

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