Re: About the HIP security model (was Re: New multi6 draft: WIMP)

[Pekka Nikander <pekka.nikander@nomadiclab.com>]

> ... So, I would
> expect the puzzle to vary depending on the CPU power (i.e. if high CPU
> power...it should solve fast.) I did see a work by MSR Penny Black 
> folks
> addressing this aspect.

We did consider Mike Burrow's memory bound functions about
a year ago, after their publication at NDSS.  However, the
general feeling was that they were too new (too little analysis)
and too unclear from IPR point of view.  Hence, the decision
back then was to use SHA-1 for now.  Of course, the decision
can be reversed if it becomes clear that the memory bound
functions (or some other form of puzzles) works better, and
is sufficiently IPR free.

--Pekka N.