I have a general question that I once knew the answer for but am no longer
sure that is the case.
The SMIME-TYPE attribute was defined so that a mime-level processor could
have some idea of the content type without having to pull apart the message
and look at the contentHint attribute or the innermost eContent. (Or at
least that is what I remember it as being for.) This being the case, what
is the correct value of smime-type on a triple wrapped message with a
signedReceipt as the content? It is signed-data or signed-receipt. Should
the answer change if the inner mime-layers were to be omitted (relevant for
the X.400 case).
Does the answer change if you have an encrypted receipt (i.e. E(S(Receipt)))
What is the correct value of smime-type now? signedReceipt or
encrypted-data? Again does the answer change if the mime layer were to be
omitted.
Signed-receipt means that the top level processor knows what is going to
happen before it gets there and can make intellegent decisions.
Signed-Data is "correct" because the encapsulated content contained in this
SignedData object is id-data or MIME content.
NOTE: For the simple case of data (or MIME) content the question is
accedemic as signed-data and encrypted-data both imply data content.
My original answer was the the correct answer is that signed-receipt should
be propigated up over all of the layers, but I don't find any statements
about this in either the message or ESS RFCs.
jim