John,
MSP receipt handling allows at least two _policies_.
What I am proposing is a third policy where the recipient and sender
engage in an all-or-none exchange of a receipt for a message. This fare
exchange is guaranteed by using cryptography. The recipient will not be able to
read the message before the receipt is received by the sender. Note that this
is achieved by cryptography and not by relying on an implementation of the UI.
Note further that the syntax and protocol of receipt handling (e.g.
when and whether a receipt token is returned to the requester) has
_nothing_ to do with the semantics.
Agree. Need a policy/lawyers in addition to mechanism. The mechanism can,
however, make the dispute resolution easier (e.g. by having signed information
on critical transactions available).
Ali