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i'm using Hashcat for a while & try to solve this challenge: is this possible to crack at least half the possibilities combinations password of 10 character using 94 characters from keyboard with md4 hashing. I calculated & there 53,861,511,409,489,970,176 combinations, there was a service that offer using 2petaflops supercomputer for free, how fast would it be if i run on it?

  • Depends how long the supercomputer actually takes to calculate a hash (or, possibly more usefully, how many hashes it can compute in a second) - they aren't always heavy on floating point operations (crypto.stackexchange.com/questions/2715/…) – Matthew Jul 23 '18 at 8:35
  • That's about 10000 billions hashs per seconds. So far, single computer seems to go to 50G/s with some old hardware, so you would need like 200 computers like this in parallel. Another more recent benchmark shows 350G/s so now, find 30x more GPUs or get 30 computers like that. – Xenos Jul 23 '18 at 8:40
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    There are a lot of questions on this site that pretty much ask for the same but with different numbers (and with a different "super computer") in mind. Take this search query and have fun. – Tom K. Jul 23 '18 at 8:47
  • Nothing a few dozen recent GPUs can't handle. – Overmind Jul 23 '18 at 9:08
  • @Overmind can you suggest some GPU model for this? – Dan Minh Toan Jul 23 '18 at 9:40
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Yes, it's possible and it can even be done relatively fast.

Any High End Radeon manufactured in the last years (anything since 5870 forward (and above at performance) but preferably RX580/570 or Vega) or the 1070/1080 series (even 1060 can do relatively good). A good performance reference is for the card to have at least 2T-FLOPs processing power (which all mentioned ones have).

If we take the example of the minimum I stated: Radeon 5870 - near full processing power will try the number of combinations you stated (53E) in approx 283 days. A 1060 half that. One RX580 1/3 that (<95 days). 4xRX580 can do it in under 25 days.

If you use more cards you get less time.

And since 2 TerraFLOPs can do it in 283 days, 2 PetaFLOPs (that you mentioned as a service) can do it in 0.276 days - aka under 7 hours.

Note: the above assumes a good software is used that can take advantage of near the full processing power of a card.

Note 2: For only half of your stated value, of course, only have the specified time will be required.

  • Side note: it's often easy to parallelize a brute force shared across identical hardware by well choosing you pattern (62 parallel computers running a [a-zA-Z0-9] brute force can be parallelized by setting the 1st character for each of them) – Xenos Jul 24 '18 at 8:02
  • Yes, that is a good way to manually allocate tasks across multiple hardware devices. – Overmind Jul 24 '18 at 10:55

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