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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

#51

Post by nitin_flanker »

algorias wrote: post #47
lightedman wrote: post #42

Earlier quoted context omitted.

Process of elimination restricts character and symbol sets, generally, narrowing your set of possible combinations greatly. The best way to crack a password isn't to brute-force it first, it's to first analyze who made the password, and the password system, to narrow down all possibilities before you try brute-forcing. Example; if a person is American, you can pretty much assume they're restricted to the typical US k…

I believe the poster upthread already considered only restricted characters (upper + lower + digits), so the difficulty they stated is what remains after your analysis. > Man can make it, man can break it, there is simply no exception. Nice platitude, but this is simply not true.

Rightly said. Even after we narrow down all the possibilities, there are still some common symbols that usually get used in passwords (%, $, @, etc.)

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

#52

Post by mtgx »

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…

> Moore's Law is still alive and kicking (contrary to what many claim)!

That statement is so often misunderstood, in multiple ways.

First off, Moore's Law isn't technically about performance increases. It's about doubling of transistors every 2 years on the same die space. We still got that on CPUs until very recently, even though CPU performance has stopped doubling every 2 years like 15 years ago. But now even the transistor count doubling doesn't happen every 2 years - for CPUs. If that were to happen we'd all have 32- or 64-core laptops by now. And even then the performance wouldn't be anywhere close to 64x (compared to single core).

The second misunderstanding, which exists in your post, too, is that most people refer to Moore's Law dying when they talk about CPUs (especially if we discuss performance).

However, GPUs have indeed kept doubling or so their performance every 2 years, also until very recently. Now it's more like a 30% improvement per year, or 70% improvement every 2 years, which is still way better than CPUs.

And the reason for this is because GPUs pretty much scale with number of cores. If you have 4000 CUDA cores in 2017 for 150W TDP and a $1000 price, then you're going to have let's say 7000 CUDA cores for 150W TDP and $1000 price in 2019, and the performance will be 70% greater. It doesn't work like that for CPUs, and it hasn't for like 15 years.

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

#53

Post by nikcub »

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…

> 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.

Password matching is the low hanging fruit, I usually run them on a regular server.

Where you need the large GPU workloads is in applying rules to these lists and in generating variations. There is also work in generating the rule files themselves.

The good rule sets like dive[0] have 1.2M+ rules[1]. Run that again through your 20GB list and you'll see quickly why you need many GPU's :)

[0] https://hashcat.net/wiki/doku.php?id=rule_based_attack

[1] you don't need that many rules, it is very rapidly diminishing returns after ~60% cracked and thousands of rules.

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

#54

Post by andruby »

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…

> incidentally posting this machine on HN is how I got pointed to Bitcoin thanks to the reply of a HN user :)

Mining in 2010 with such a machine. That must have yielded a considerable ROI.

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

#55

Post by konceptz »

ASlave2Gravity wrote: post #48
pmontra wrote: post #34

Earlier quoted context omitted.

Seconded. The bitcoin to USD ratio is like 1 to 2700 right now http://www.xe.com/currencycharts/?from=XBT&to=USD

What's caused the price to rise so much the past few months?

It's also being used to hide cash in China.

http://www.cnbc.com/2017/05/23/jeff-gundlach-has-a-theory-on...

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

#56

Post by ihalip »

ASlave2Gravity wrote: post #48
pmontra wrote: post #34

Earlier quoted context omitted.

Seconded. The bitcoin to USD ratio is like 1 to 2700 right now http://www.xe.com/currencycharts/?from=XBT&to=USD

What's caused the price to rise so much the past few months?

IMO, this happened because of the Ethereum ICO fever. While there are a number of exchanges that allow you to trade USD -> BTC, there aren't as many that allow trading USD -> ETH. So there are people who might have traded USD -> BTC -> ETH, and this increased demand for BTC.

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

#57

Post by beefsack »

We all know MD5 is broken, but looking at it from purely a brute-force perspective:

If you look at a US English keyboard, you've generally got 47 unique character keys. Let's double it and say there are 100 different characters you can type just using the character keys and shift.

This machine could brute-force crack any 6 character password in under 4 seconds, any 7 character password in just over 6 minutes, and any 8 character password in just over 10 hours.

And that's using the least efficient method known.

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

#58

Post by matt4077 »

nikcub wrote: post #50
Roritharr wrote: post #30

Earlier quoted context omitted.

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

You can get over that feeling very quickly by reminding yourself to focus on what you might be missing out on today that you don't want to regret in years from now.

Or, alternatively, by remembering the efficient market hypothesis. And going for ice cream with someone you like.

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

#59

Post by matt4077 »

ASlave2Gravity wrote: post #48
pmontra wrote: post #34

Earlier quoted context omitted.

Seconded. The bitcoin to USD ratio is like 1 to 2700 right now http://www.xe.com/currencycharts/?from=XBT&to=USD

What's caused the price to rise so much the past few months?

Speculation. FOMO.
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