At 8:14 PM -0700 7/24/97, Blake Ramsdell wrote:
On Thursday, July 24, 1997 4:13 PM, John Gardiner Myers
This "binary MIME object" problem is also an issue for the
application/pkcs7-mime type. I've already heard reports of
noninteroperability between different S/MIME implementations, because
some senders imbed binary MIME objects inside an application/pkcs7-mime
objects and some readers cannot handle binary MIME objects contained
inside application/pkcs7-mime objects.
I'd like to suggest that we get tough with the language which keeps the
interoperability, but loses the ability to slim down the message. If
that's too harsh, then my next choice would be preferBinaryInside.
I agree with Blake, et al. Let's make it 7-bit only and disallow all the
binary stuff. The reasons I'd give are difficulty of implementation and
interoperability with the installed base. Also consider that protocols
like IMAP can't handle binary MIME (unless something changed recently).
Let's change the document for the next draft and let those that don't like
it make their arguments.
That of course means we must change the default CTE to 7-bit (section
3.1.2), which of course means if there is no CTE header, the 7-bit should
be assumed. I believe this change is important even if we allow binary CTE
because that is the default in the 822/821 context, and we want to be able
to remove the security layers and drop messages into the environment
without changing the mime object/message.