[foofus-tools] off-Topic: Bitcoin and password cracking?

[Richard Miles]

Hi foofus members,

First of all sorry for off-topic, but this sound interesting and I
know that foofus guys are always playing with everything that is
related with hacking and password cracking so I decided to send it
here, I hope you don't mind.

I never used Bitcoins and it's not very popular with my circle of
friend, but a presentation entitled "Hacking the Global Economy with
GPUs or How I Learned to Stop Worrying and Love Bitcoin" called my
attention, however it's very confuse (at least to me).

http://this-download-would-be-faster-with-a-premium-account-at-good.net/dl/1483089/0/0/1313942385/219be7f80763b020d6319ca8e9afaa03e0a035d9/k4r3lj/DEFCON19/DEFCON-19-Skunkworks-Bitcoin.pdf

I'm a bit unsure about what is the goal of the preso and real usage of
GPUs and hash cracking with bitcoins. The author gave the idea that it
can be used as a botnet and since there is a lot of GPU systems it
could be a wonderful network for distributed hash password cracking if
the price to do it is acceptable (since Amazon EC2 is expensive).
Anyone has any experience with it?

Or, maybe the goal of this people is just use Bitcoin to be rich with
all this power based on the GPUs "printing" money, which also is a
confusing concept to me and Wikipedia say it may not be that easy
anymore

"The proof-of-work problems are especially suitable to GPUs and
specialized hardware. Because of the growing computing power behind
the system driving the difficulty to high levels, individual
contributors with typical CPUs are no longer likely to solve a block
on their own but can still receive part of the Bitcoin generated in a
new block by contributing their processing power to a mining pool.[26]
This increased difficulty makes it cost prohibitive for an attacker to
perform double-spending attacks so it is beneficial to the system."

All answers are very welcome and sorry for off-topic.

Cheers