Re: [Hipsec] Memory-bound puzzles in BEX

[Miika Komu <[e-mail]>]

On 27/05/10 15:18, Tobias Heer wrote:

Hi Tobias,

I'd be leaning a bit towards CPU-bound puzzles but perhaps just because 
we've been just using them earlier. Big puzzles of both types can be 
problematic for e.g. sensor devices with limited memory and CPU 
capabilities, so in that sense it's a tie. Perhaps it's actually battery 
life (drained by CPU usage) time that seems to suffer from technological 
advances, so perhaps that could used to promote either of the types.

The current CPU-based puzzles are parallelizable which means that a bot 
net could be used for solving a puzzle in a distributed way. As an 
alternative, we could also switch to serialized puzzles. Anyway, I don't 
think this has big impact - I guess it's ok to distribute the solving in 
the end.

> Hi everyone,
>
> RFC5201 states that memory bound puzzles should be reconsidered for future versions of the document. The exact text is here:
>
> NOTE: The protocol developers explicitly considered whether
> a memory bound function should be used for the puzzle
> instead of a CPU-bound function.  The decision was not to
> use memory-bound functions.  At the time of the decision, the
> idea of memory-bound functions was relatively new and their
> IPR status were unknown.  Once there is more experience
> about memory-bound functions and once their IPR status is
> better known, it may be reasonable to reconsider this
> decision.
>
> I am asking the list if the time for reconsideration has come. Should we delve deeper into non CPU-bound puzzles for RFC5201-bis or should we keep this note for future revisions.
> Is there anyone with a background on memory-bound puzzles interested in having them in RFC5201-bis?
>
> Best regards,
>
> Tobias
>
>
>
>
>