BCrypt + GTX670 = 6 c/s?
#11
Quote:Hello Anton,

What atom meant is that attack depends on the number of hashes you are trying to attack (this correlation is linear, e.g attacking 5 hashes will yield 1/5 of the attack speed).

Another reason for the slow speed could be the iterations count which is "embedded" in the hash string. I guess you could post the hash prefix and that's not against the forum rules, but basically the bcrypt hashes look like:

$2$<iterations>$<salt>$<base64-encoded hash>

The common hashes have "5" for iterations (which actually means 2^5=32), so they start with $2$05$

However some implementations might increase the iterations count.

Keep in mind that bcrypt is quite an anti-GPU algorithm as it requires a lot of memory accesses. A mid-end CPU would often crack it faster as compared to a high-end GPU.

Hello gat3way and thanks for an in-depth reply.

I do (or so I hope) understand the premise, but real-life tests (as per my previous post with just one hash) make no difference at all.

The hash in question starts with $2a$12$. I'm not sure what to make of it, bcrypt-wise, since I never dealt with it before. Looking at that 12 pretty much means I'm f*cked, do I understand this correctly? And you have a single-digit number before the first separator (yours is $2$, mine is $2a$), does that account for anything?

I'm pretty much alright on the memory front with 32GB of RAM and the latest 3.6ghz i7. Or so I thought.

Anyway, thanks again. That was enlightening.

Anton.


Messages In This Thread
BCrypt + GTX670 = 6 c/s? - by wflme - 01-16-2013, 04:13 PM
RE: BCrypt + GTX670 = 6 c/s? - by eljolot - 01-16-2013, 04:40 PM
RE: BCrypt + GTX670 = 6 c/s? - by unix-ninja - 01-16-2013, 04:41 PM
RE: BCrypt + GTX670 = 6 c/s? - by wflme - 01-16-2013, 04:46 PM
RE: BCrypt + GTX670 = 6 c/s? - by unix-ninja - 01-16-2013, 04:54 PM
RE: BCrypt + GTX670 = 6 c/s? - by blandyuk - 01-16-2013, 05:31 PM
RE: BCrypt + GTX670 = 6 c/s? - by wflme - 01-16-2013, 06:49 PM
RE: BCrypt + GTX670 = 6 c/s? - by wflme - 01-16-2013, 07:59 PM
RE: BCrypt + GTX670 = 6 c/s? - by epixoip - 01-16-2013, 08:38 PM
RE: BCrypt + GTX670 = 6 c/s? - by gat3way - 01-16-2013, 08:06 PM
RE: BCrypt + GTX670 = 6 c/s? - by wflme - 01-16-2013, 08:21 PM
RE: BCrypt + GTX670 = 6 c/s? - by epixoip - 01-16-2013, 08:41 PM
RE: BCrypt + GTX670 = 6 c/s? - by wflme - 01-16-2013, 08:53 PM
RE: BCrypt + GTX670 = 6 c/s? - by Rolf - 01-16-2013, 10:11 PM
RE: BCrypt + GTX670 = 6 c/s? - by wflme - 01-16-2013, 10:20 PM
RE: BCrypt + GTX670 = 6 c/s? - by atom - 01-16-2013, 06:06 PM
RE: BCrypt + GTX670 = 6 c/s? - by radix - 01-16-2013, 11:14 PM
RE: BCrypt + GTX670 = 6 c/s? - by wflme - 01-17-2013, 12:11 AM
RE: BCrypt + GTX670 = 6 c/s? - by wflme - 01-17-2013, 12:12 AM
RE: BCrypt + GTX670 = 6 c/s? - by wflme - 01-17-2013, 12:15 AM
RE: BCrypt + GTX670 = 6 c/s? - by radix - 01-17-2013, 12:50 AM
RE: BCrypt + GTX670 = 6 c/s? - by wflme - 01-17-2013, 12:54 AM
RE: BCrypt + GTX670 = 6 c/s? - by atom - 01-17-2013, 12:22 PM
RE: BCrypt + GTX670 = 6 c/s? - by Bitweasil - 01-18-2013, 02:12 AM