In <200105041731(_dot_)NAA11008(_at_)astro(_dot_)cs(_dot_)utk(_dot_)edu>
Keith Moore <moore(_at_)cs(_dot_)utk(_dot_)edu> writes:
Is upconversion actually allowed by RFC 2821? Because it will break any
PGP/MIME signature,
so will downconversion. having the signature on the transfer-encoded
form is just broken - because this form doesn't get preserved end-to-end.
Yes, I was confusing two things. It is Content-MD5 that is safe through
downconcersion, but may be proken following a subsequent upconversion (see
recent discussions on this list).
AFAIK the only reason upconversion would ever break content-md5 is (1)
The content was incorrectly canonicalized to begin with or (2) The
upconversion produced something that was intrinsicly incompatible with the
CTE chosen for the converted result.
Please elaborate if you are thinking of some other case.
Ned