[hashcash] Re: Hashcash vs. Time?

  • From: "Eric S. Johansson" <esj@xxxxxxxxxx>
  • To: hashcash@xxxxxxxxxxxxx, scott_hashcash@xxxxxxxxxxxxxxxxx
  • Date: Tue, 13 Apr 2004 09:42:27 -0400

Scott Robinson wrote:

> How does hashcash stand up to Moore's law? How is this not a temporary 
> solution?

http://www.camram.org/frequently-raised-objections.html
question 5

although as I was rereading what I had written, I think this elaboration 
may also help.


all proof of work puzzles be it memory or computation will eventually 
degrade to the same thing courtesy Moore's Law.  All you are doing is 
exercising the number of transistors you can pack onto a chip.

The only way to cope with Moore's Law is through a mechanisms of 
communicating local coverage postage rates.  Local as defined by the 
people you communicate with.

If you know the rates expected by all of your peers, your own processing 
capability, and the stamp values of any spam, you can then set your own 
rate.  and yes, this does imply a need for some form of insufficient 
postage mechanism.  It will probably need a trigger which won't fire 
unless the incoming postage is within three bits of your rate.  this 
trigger is so the spammers can't jojob easily.

If you're worried about the low-end systems being locked out because of 
long computation times, in the camram implementation, I'm not sending 
stamps unless they are to people I don't know.  Which lets me generate a 
much bigger stamp because I'm not doing it as often.  I also get 
additional immunity from stamp size by generating stamps in background. 
  You don't have to sit there waiting for the stamp before you can move 
onto the next message.

---eric



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