[mnet-devel] Grid Of Trust -- pre-design

[Jim Dixon]

On Tue, 9 Dec 2003, [iso-8859-1] Some Guy wrote:

> So we can agree for that million node network an advesary can launch
> nodes into any cell he chooses if he can do somewhere between 500,000
> to 1,000,000 CPU days of work every month.

My simulation said 4000 desktop machines, less than 200 days.  You
suggested that the actual cost would be two orders of magnitude less.
I then suggested that for serious adversaries we were then talking
about hours to fill 2^16 cells.

You then suggested that you make this a monthly charge.  That is, all
users have to pay 1 CPU-day in hashcash a month.

I then pointed out that you would never ever get the million node network,
because while the hashcash bit wouldn't put any sweat on the brow of the
Bad Guys, it would certainly drive away ordinary users.  In your real
hashcash network, you might possibly get 2^6 users, maybe even 2^8.

> Hypothesis:  Ok this will probably annoy you even more than that
> formula, but I've got an idea that to cover all cells K is O(W^2).

In the simulation, for W = 2^16, K was about 160 * 4000 = 640,000,
something over 2^19.  I certainly wouldn't call this O(W^2) == O(2^32),
something over 4 billion.

> By the way I think I know how to make it so that a good user can avoid
> redoing the hash cash every period, by storing an arbitrarily large
> file.  This could force the advesary to either redoo all that K hash
> cashes every iteration or store K*<the file size>.
>
> So maybe we let that size be 10GB.  It still takes about a day to get
> a working ID but then you just store a 10GB file.  Every period you
> just have to do a quick lookup on your drive.  Of coarse the adversary
> could also avoid doing the hash cashes, by buying K*10GB of space.

The adversary doesn't need K drives.  He need one drive per cell, which
is 2^16, about 64,000.  10G drives in this quantity would cost perhaps
$20 each, so K 10G drives would cost about $1,640,000.  He would also
need a 2 Gbps connection to the Internet.  Guesstimated price somewhere
over $100,000 a month.

> How much is 10PB cost?
>
> Storage has the benifit that tieing it up doesn't annoy as much.

Your end users have to buy a 10G drive each and then dedicate 32K to
your constant churning of those drives.  You are going to have to fork
out for a million 10G drives, one for each of your users, or perhaps
100,000 100G drives, plus machines, plus rack space in a colo center.
However you slice it, this would not be cheap.  50,000 1U PCs?  More
than 1,000 racks?  It has to cost _you_ more than $25 million in up-front
costs.

We haven't included the 32 Gbps network cost of driving this huge
verification program.  I haven't been in the game for a while, but I think
that that load would put a severe burden on the global Internet. But many
ISPs would be happy to bid on the contract.  I would guess that it
wouldn't cost more than something in the tens of millions of dollars a
year for the service.

Where does the revenue come from?

--
Jim Dixon  jdd at dixons.org   tel +44 117 982 0786  mobile +44 797 373 7881
http://jxcl.sourceforge.net                       Java unit test coverage
http://xlattice.sourceforge.net         p2p communications infrastructure



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