Quote from: nguoinhaque on July 03, 2012, 08:21:19 PM

Quote from: crazyates on June 17, 2012, 12:15:32 AM

Correct me if I'm wrong, but this can't happen with their ASICs. Password cracking works backwards from hashing, right?

The general idea of mining is to run thru a SHA256 hash twice. They take x and turn it into y like this:

y = (SHA256 (SHA-256 (x)))

This is assuming their ASIC does both steps at once. Their ASIC may only do one hash at a time, but it would still look like this:

z = (SHA256 (x))
y = (SHA256 (z))

For password cracking, you would need some way to go from an already encrypted password that's only gone through one SHA256 encryption (z, in the example above), and un-encrypt it into x. It was my impression that this sort of password cracking works backwards from bitmining. The ASIC could be use to encrypt passwords, but there would be no use for something that fast.

Bitmining: x --> SHA256 --> z --> SHA256 --> y
Password: x --> SHA256 --> z
Cracking: z --> CRACK --> x

Does that make sense? Anyone more knowledgeable care to point out any blatantly obvious holes in my reasoning?

We have hashed password: z
We need to know the password: x
Solution: Just calculate y = SHA256(z). Then use ASIC to search for x when we already know y

A) Hashing an already hashed password does nothing for us. How is an ASIC (that only does hashes) gonna find a twice hashed password?

B) This discussion has already run its course, and been answered. I was corrected 2 posts down:

Quote from: MrTeal on June 17, 2012, 02:52:10 AM

For cracking, you have the hash of the password. You then take your password guess, hash it, then compare that hash to the value you have. Rinse and repeat several trillion times.