Re:1Password GPU brute-force with 3M hash/s
by metachris on Tuesday April 16, 2013 @07:21PM
(#5561579)
> 3^48/(3M attempts/s) ~= 3 years
But that's just with 2 GPU's! Any larger bitcoin miner has a few hundred (up to many more) of these graphics cards running. 100 GPUs would require only 20 days! Any larger entity could easily setup 1000 GPUs which cuts it down to 2 days, etc.
Probably there will be password cracking pools, similar to altcoin mining pools, which pay for your GPU resources in bitcoins.
Re:1Password GPU brute-force with 3M hash/s
by crisnoble on Tuesday April 16, 2013 @07:27PM
(#5561597)
They will need to do something with their rigs once mining gets too hard and the payouts too small.
Re:1Password GPU brute-force with 3M hash/s
by aidenn0 on Tuesday April 16, 2013 @07:33PM
(#5561627)
Hmm, what's the opportunity cost (in terms of average BTC not mined) for doing 2^48 attempts?
Re:1Password GPU brute-force with 3M hash/s
by shawabawa3 on Wednesday April 17, 2013 @08:23AM
(#5564008)
It takes on average 2^54 hashes to discover a block at the current difficulty. So 2^48 attempts is 2^-6 (1.5%) of a block on average. A block is currently worth ~$2000, so 1.5% of that is ~$30
"A user-selected eight-character password with numbers, mixed case, and symbols, reaches an estimated 30-bit strength, according to NIST" [1]
2^30/(3M attempts/s)=358s
A completely random 8-character password from a space of 64 characters (upper, lower, number + 2 symbols) is 48 bits:
3^48/(3M attempts/s) ~= 3 years
Multiply by 64^N for longer passwords (so >180 years for a 9 character password)
The reason for the difference is that user-selected passwords are (on average) not as good as random passwords.
[1]http://en.wikipedia.org/wiki/Password_cracking#Time_needed_f...