It is not totally clear to me that doing Base64 encoding on binary
attachments is the right long term thing to do. I've seen criticism
of MIME (as compared to X.400) in that MIME requires such an encoding.
I hope I haven't missed your point, but if some criticize MIME
for "requiring" Base64, blame that on dumb MUAs (of which I too am guilty).
I use one particular MUA that Base64 encodes *every* attachment.
This is mindless. The app didn't bother to make any considerations.
Certainly if the attachment were, say, a code fragment then Base64
is quite unnecessary.
X.400 has its own ASN.1 encoding, but that does not involve translating
every byte of a (potentially large) binary attachment.
Well ... there may be then at least one thing from X.400
that I want to see us keep in the future. Don't inhale. ;-)
Mark