🚀 go-pugleaf

cbbrowne@csi.uottawa.ca (Christopher Browne) writes:

|> If that $56 figure is faintly accurate, then I expect that the NSA
|> must have some rather high-speed hardware, probably specialized to
|> DES, that costs quite a bit less than anyone expected.  I would have
|> expected a somewhat higher bill.
|> 
|> I can give some basic "blanks" to fill in:
|> 
|> a) Number of messages processed: _____________
|> 
|> b) Mean Size of messages processed:   _____________  (may be important)
|> 
|> A * B = "total ciphertext"
|> 
|> c) Cost of electricity and staffing, per hour, for the NSA "DES
|> Breaker" computer:                  ____________
|> 
|> d) Average time to decrypt 1K of message on the "DES Breaker":
|> ______________
|> 
|> Actually, one can probably get that $56 just out of figures b), c) and
|> d).
|> 
|> $56 = (b) * (c) / (d)
|> 
|> I'm ignoring capital costs, in this analysis, but I'd suspect that so
|> does the NSA.  Governments don't tend to consider "capital costs" to
|> be REAL costs, for a variety of reasons.
|> 
|> And if anyone wishes to publicise the values b), c) and d), that's
|> THEIR choice.  Those three numbers are probably considered QUITE
|> secret.

You need single-chip search engines (custom-built IC, not standard 
DES chips) with a gate delay of 3 nanoseconds to get a 1-microsecond
search time.  You make a machine with 100 racks of 10,000 IC's/rack.

in 1976, given economies of scale, each IC would cost ~$10 
($10M/machine).  Allow a factor of two, for other hardware and you
pay $20M/machine.  Amortize costs over 5 years, and you pay $10K/day.

10**6 keys     10**5 sec     10**6 IC     10**17 keys
----------  X  ---------  X  --------  =  -----------
  sec/IC          day           1             day

10**17 searches ~= 2**56 searches = 1 exhaustive search.

1 exhaustive search/day at $10K/day = $10K/exhaustive search.

These are 1976 figures.  Even if we are optimistic by an order
of magnitude, the cost of computation falls in 5 years by a factor 
of 10; in 15 years (by now) by 1,000.  This results in a cost of
~$10/exhaustive search.

(The preceding is condensed from a talk given by Prof. Martin E. 
Hellman of Stanford University at the RSA Data Security Conference,
1/17/93)

-- 
Peter K. Boucher
--
RIPEM public key available upon request.