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Password Cracking with 8x Nvidia GTX 1080 Ti GPUs

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Re: Password Cracking with 8x Nvidia GTX 1080 Ti GPUs

#21

Post by manav »

walrus01 wrote: post #2

as with most really high electrical loads, if you can operate it remotely, do so. There's places in North America near major hydroelectric dams with electricity that costs $0.03 to $0.045 per kWh. Running something like this and the cooling needed for a 3kW thermal load on California electrical prices is a good way to burn money.

I have some 4u servers and I found that with 4x in a rack that's already to dense and the temperatures too high with the consumer level cards that need active cooling.

On the other hand, in CA more rack space was relatively cheap.

Re: Password Cracking with 8x Nvidia GTX 1080 Ti GPUs

#22

Post by Const-me »

I’ve once used my PC for the same thing, the result was OK. Based on raw performance, my GTX 960 GPU is 4.5 times slower than a single 1080 Ti, and thus 36 times slower than 8x 1080 Ti’s.

My GPU was able to try 20GB passwords in a couple of minutes. That was the largest password list I’ve found on the internets.

However, neither system can brute force even a short 8 characters password. If the password is lower+upper+digits, that’s (26*2+10)^8=2.14E+14 passwords. This number is way out of range even for a PC with 8x 1080 Ti.

Those GPUs are only useful in a very small number of corner cases.

Re: Password Cracking with 8x Nvidia GTX 1080 Ti GPUs

#23

Post by mrb »

Const-me wrote: post #22

I’ve once used my PC for the same thing, the result was OK. Based on raw performance, my GTX 960 GPU is 4.5 times slower than a single 1080 Ti, and thus 36 times slower than 8x 1080 Ti’s. My GPU was able to try 20GB passwords in a couple of minutes. That was the largest password list I’ve found on the internets. However, neither system can brute force even a short 8 characters password. If the password is lower+upper…

2.14e14 is nothing. 8x 1080 Ti can crack that in less than 15 minutes (NTLM, MD4, MD5).

Re: Password Cracking with 8x Nvidia GTX 1080 Ti GPUs

#24

Post by cleeus »

As a dev you should take a look at the difference of hashes/s of the different algorithms. Some are measured in GH/s, some in MH/s, some only kH/s. E.g. MD5 is way faster then SHA256. So if you only use a strong hash for ensuring data integrity in the absence of adversaries and performance matters, you may prefer MD5 even in these days.

Re: Password Cracking with 8x Nvidia GTX 1080 Ti GPUs

#25

Post by ComputerGuru »

cleeus wrote: post #24

As a dev you should take a look at the difference of hashes/s of the different algorithms. Some are measured in GH/s, some in MH/s, some only kH/s. E.g. MD5 is way faster then SHA256. So if you only use a strong hash for ensuring data integrity in the absence of adversaries and performance matters, you may prefer MD5 even in these days.

There's no good reason to use md5, period. If performance matters and security doesn't, use something like mmhash3. If security matters and speed doesn't, use something like SHA-512 (optionally truncated to 256 bits). If both matter, use something like siphash if a prf will do or blake2 if you need a true, high-speed cryptographic hash.

(Actually, besides portability and interoperability, there's probably no good reason to use SHA-anything over blake2. Although if you are working in environments that provide hardware crypto support (Intel SHA Extensions on Atom, now also supported on Ryzen so maybe we'll see it on the desktop, too), SHA becomes faster than blake2 and you should use that instead.)

If at any point you find yourself in a situation where your hash being computed too fast poses a security risk, that should be a HUGE warning. Hashes should be fast, cryptographic or otherwise. If you need a "slow hash" you are probably looking for a derivation algorithm and not a hash and should be looking at scrypt, bcrypt, or even pbkdf2.

Re: Password Cracking with 8x Nvidia GTX 1080 Ti GPUs

#27

Post by ComputerGuru »

walrus01 wrote: post #2

as with most really high electrical loads, if you can operate it remotely, do so. There's places in North America near major hydroelectric dams with electricity that costs $0.03 to $0.045 per kWh. Running something like this and the cooling needed for a 3kW thermal load on California electrical prices is a good way to burn money.

People tend to forget about "the flyover states," but here in Chicago we get ~55% of our power (that was back in 2011 [0]) from renewable and nuclear sources, and have access to similar pricing as a result.

[0]: http://chicagoloopster.medill.northwestern.edu/2012/01/27/so...

Re: Password Cracking with 8x Nvidia GTX 1080 Ti GPUs

#28

Post by Const-me »

mrb wrote: post #23
Const-me wrote: post #22

I’ve once used my PC for the same thing, the result was OK. Based on raw performance, my GTX 960 GPU is 4.5 times slower than a single 1080 Ti, and thus 36 times slower than 8x 1080 Ti’s. My GPU was able to try 20GB passwords in a couple of minutes. That was the largest password list I’ve found on the internets. However, neither system can brute force even a short 8 characters password. If the password is lower+upper…

2.14e14 is nothing. 8x 1080 Ti can crack that in less than 15 minutes (NTLM, MD4, MD5).

This page says 8x 1080 Ti can do 1.3e10 hashes/sec for NTLM:

https://gist.github.com/epixoip/a83d38f412b4737e99bbef804a27...

To test 2.14e14 passwords, you need 4.5 hours.

Add a single extra character to that password and the time will become too long regardless on your hardware.

Re: Password Cracking with 8x Nvidia GTX 1080 Ti GPUs

#29

Post by vit05 »

mrb wrote: post #18

In 2010 I built an 8-GPU machine[1] (4 dual-GPU AMD HD5970) and wrote an MD5 bruteforcer (then faster than hashcat), doing 28.6 then 33.1 billion passwd hashes/sec with a software optimization: http://blog.zorinaq.com/whitepixel-breaks-286-billion-passwo... It's interesting to note that 6.5 years later a single GPU like the Nvidia 1080 Ti can match the whole 2010 machine (32 billion hashes/sec). This is a doubling of…

"At a current market value of about USD$0.22 per coin" wow

Re: Password Cracking with 8x Nvidia GTX 1080 Ti GPUs

#30

Post by Roritharr »

vit05 wrote: post #29
mrb wrote: post #18

In 2010 I built an 8-GPU machine[1] (4 dual-GPU AMD HD5970) and wrote an MD5 bruteforcer (then faster than hashcat), doing 28.6 then 33.1 billion passwd hashes/sec with a software optimization: http://blog.zorinaq.com/whitepixel-breaks-286-billion-passwo... It's interesting to note that 6.5 years later a single GPU like the Nvidia 1080 Ti can match the whole 2010 machine (32 billion hashes/sec). This is a doubling of…

"At a current market value of about USD$0.22 per coin" wow

The regret I feel having given away all of my 100 bitcoins at that price point will forever haunt me.
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