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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

#61

Post by masklinn »

cm2187 wrote: post #17

bcrypt: 21kH/s scrypt: 750kH/s The author didn't mention the work factor so I don't know how comparable the results are. But I thought the merit of scrypt over bcrypt was that it was memory hard, i.e. hard to run on a GPU. It doesn't seem to be the case.

> The author didn't mention the work factor

It's not really the author, it's the Hashcat benchmark which they've just straight run onto the system, there's the exact same problem with e.g. PBKDF2:

    Hashtype: PBKDF2-HMAC-SHA256
    […]
    Speed.Dev.#*…..: 14417.6 kH/s

    Hashtype: Django (PBKDF2-SHA256)
    […]
    Speed.Dev.#*…..: 729.6 kH/s
or

    Hashtype: PBKDF2-HMAC-SHA512
    […]
    Speed.Dev.#*…..: 4974.7 kH/s

    Hashtype: OSX v10.8+
    […]
    Speed.Dev.#*…..: 147.2 kH/s
(it's my understanding that current OSX uses PBKDF2-SHA512)

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

#62

Post by jacquesm »

dragontamer wrote: post #16

> The GTX 1080 Ti is the go-to value card for deep learning at the moment. Ah, that explains a lot. I recall seeing that AMD cards are being used for most of the Bitcoin / Etherium stuff right now, so I thought it was odd to see team-green used in this case. IIRC, AMD cards have faster integer performance, but are slower in floating-point than the NVidia cards. Password-cracking is primarily integer-based however, so…

The major difference between AMD and Nvidia for mining/hashing and other integer algorithms is that if that algorithm contains a 32 bit 'ROR' (rotate right) then AMD will do that in one tick whereas on an Nvidia card you would need 3 ticks.

That single low level detail meant that AMD destroyed Nvidia when it came to computing hashes quickly because the innermost loops of those algorithms contain a ROR.

Since then the situation has changed, NVidia has improved their performance but bitcoin mining has moved to ASIC almost entirely and for other algorithms AMD still seems to come out ahead of Nvidia.

For deep learning the situation is reversed, there it is almost entirely Nvidia, a major reason is that Nvidia put substantial effort in low level libraries that get the maximum out of their hardware for deep learing applications.

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

#63

Post by Retric »

astrodust wrote: post #14
hughes wrote: post #10

Earlier quoted context omitted.

99% of the electricity in Quebec is from hydroelectric dams. This is how the costs are kept so low, and you don't really have to worry about resulting greenhouse gas emissions.

Semi-sorta. It did involve flooding huge amounts of Quebec, so there are consequences and greenhouse gas emissions due to rotting trees, but it's a different sort of equation.

If you compare X vs 1/10,000th X then the emissions from the second option are effectively meaningless.

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

#64

Post by mrb »

mtgx wrote: post #52
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…

On a GPU more transistors = more compute units = more performance. Hence my over-simplification of Moore's Law.

I strongly disagree that the rate of CPU perf improvement has slowed down "15 years ago". What a laughable statement. You have to look beyond core count to gauge performance. Microarchitectural improvements, new instruction sets (SSE, AVX), bigger caches, etc certainly still help keep the pace. Have a look: https://www.hpcwire.com/2015/11/20/top500/ In particular: https://6lli539m39y3hpkelqsm3c2fg-wpengine.netdna-ssl.com/wp...

Also perhaps you get confused by the fact the average wattage of CPUs sold to consumers is dropping. If, from the performance of a 60-70 watt Netburst Pentium 4 from 2001, you project the expected performance of a 2017 CPU according to Moore's Law, then you should look at today's 60-70 watt CPUs, not at modest 10-20 watt CPUs that seem to be quite popular these days.

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

#65

Post by cleeus »

aappleby wrote: post #36
cleeus wrote: post #31

Earlier quoted context omitted.

I have not looked deeply at mmhash3 (I guess it means murmurhash3), but wikipedia says: [...] When using 128-bits, the x86 and x64 versions do not produce the same values [...] which will make it unsuitable for cross-platform applications. I was talking about a usecase where you could also choose CRC32 from a security standpoint but want more collision resistance. How does blake2 performance compare to MD5?

The wikipedia page might be a bit misleading - there's a 128-bit murmur3 that uses 32-bit math (works well on most every processor), and a 128-bit murmur3 that uses 64-bit math (much faster on 64-bit processors, much slower on 32-bit ones) -Austin, Murmur author.

ah, so there is mm3-128-32 and mm3-128-64

that makes it actually a viable alternative to MD5

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

#67

Post by ratacat »

beefsack wrote: post #57

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…

That's assuming you're only dealing with cracking a hashed version, or you have unlimited instant opportunities to "get it right"

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

#68

Post by pfalke »

beefsack wrote: post #57

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…

As a non-infosec guy, could someone shed more light on the implications for end users?

I get that the combination of password reuse, short passwords and the fact that some services store passwords in plain text or as MD5 hashes makes it easy to break into accounts once a single service is compromised.

So my takeaway is not to use longer passwords, but to use a password manager and have unique passwords for every service. My current setup is 8 character passwords for online services (easier to occasionally type in manually).

Am I running a risk by not using 12 character passwords?

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

#69

Post by mciancia »

jrimbault wrote: post #40
dragontamer wrote: post #16

> The GTX 1080 Ti is the go-to value card for deep learning at the moment. Ah, that explains a lot. I recall seeing that AMD cards are being used for most of the Bitcoin / Etherium stuff right now, so I thought it was odd to see team-green used in this case. IIRC, AMD cards have faster integer performance, but are slower in floating-point than the NVidia cards. Password-cracking is primarily integer-based however, so…

I think (not sure) that AMD is faster per $ not faster for mining specifically ? So it makes more sense when mining for bitcoin to buy the fastest per $ cards ?

You need to count in the performance per Watt and nvidia is sometimes better when it comes to that. Anyway, with current bitcoin and ethereum price, good luck finding any high end nvidia or amd GPU - miners are buying everything

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

#70

Post by beefsack »

ratacat wrote: post #67
beefsack wrote: post #57

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…

That's assuming you're only dealing with cracking a hashed version, or you have unlimited instant opportunities to "get it right"

That's correct, but the context of this discussion is cracking hashes locally.

Note that using salts don't necessarily slow down brute-force cracking of a specific hash if the salt is known and understood.

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