I hate to rain on your parade, but...
the RC5-72 contest is pointless, unwinnable and wasteful.
The contest is scientifically pointless
. Cracking a single key
by brute force
is not rocket science
, it's been done before.
Successfully cracking that one particular key
weaken RC5-72 as a cryptographic algorithm
one bit, brute force is
the lowest common denominator attack against all algorithms.
And unlike the previous DES
challenges, this contest
cannot even serve to point out how insecure RC5-72 is, because nobody
uses RC5-72 and because...
The contest is not winnable
in a reasonable amount of time.
As of today
, distributed.net expects that keyspace
will take place in 788,747 days. For the mathematically
impaired, that's 2161 year
s. During the RC5-64 contest, it took on
average 261 days for processing speed to double; if this doubling keeps
up for 5 years (that's 7 doublings), you're only looking at another 17 years
of number crunching after
those 5 years. Do you seriously expect to keep going until 2025?
Another way to look at the situation:
buying a lottery coupon for $1, with a possible yield of $1,000,000 if
you get 7 right, has an expectation of $1 * 6.5e-8 * 1e6 = $0.01.
However, the odds of the key being found today are 0.000127%, and of the
1392922 blocks completed 8744 (0.63%) were done by the E2 team.
The odds of E2 receiving the price money tomorrow are thus
1.01e-12, or 0.000000001%. That's a lotta zeros.
But hey, you never know. With a prize money of $10000 in the offering,
we need to have a 'bet' of less than $0.000000001 ($1e-10) per day to
beat the odds of the lottery. But processor power is free, right?
Wrong. Back in the halcyon
days of RC5-56 and the DES
computers didn't make a distinction between idling
so it was a great idea to use those spare cycles for something (remotely)
. But this is no longer true: modern-day power-sucking CPUs
circuitry that lets them idle and cool off when the processor is just
s. Thus, keeping a number cruncher running 24 hours a day will
stress your processor, requiring full ventilation and running up your
To illustrate, a standard Pentium III, without the requisite array of
cooling fans, sucks down around 30W when running at full speed. Run that
sucker for 24 hours, and you've run up a bill of 0.72 kilowatt-hours, or
about 3.6¢ assuming 5¢/kW/H.
If you want to earn money for E2...
...it would be 36,000,000,000 times more efficient to buy a lottery ticket
each day. Then again, 3.6¢ a day adds up to $13.14 a year, so why
not donate the sum directly?
If you want to advance science
through distributed computing
...you might want to try folding proteins (folding.stanford.edu), finding a cure for cancer
looking for Sierpinski numbers (www.seventeenorbust.com), or even
optimal Golomb rulers (www.distributed.net/ogr/).
My elementary statistics course.
Calculations done on the back of a virtual napkin, so corrections welcome.
Lottery probability based on the Finnish model, ie. 39 balls with
7 picked and 7 needed for the grand prize.