At the same time, Microsoft has not provided even an answer
on which part
of the spec they have patent on, nor is it clear if patent
they have can
even apply as PRA algorithm has already been changed during MARID
discussion and even before that, the algorithm proposed was a fairly
obvious one and its not totally clear if you can patent thing
like that
(can you really patent an idea that person who send you email can be
identifed by either From or Sender header?).
Which is probably what the Microsoft lawyers themselves have to answer
before they decide whether they give the answer that the patent application
does not cover the scheme as currently defined or they provide alternative
wording.