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I need help.

I actually encrypted two mouths ago my external HDD with LUKS but know i have lost my password. I am so depressed because, all of my life is on this HDD.

Is there any possibility to get back my files: i think i almost know the password.

Please help me.

EDIT: 24.05.15 6:27 pm

Manumit: thank you. But the programm you send me is very expensive

jas- Thank you for your advices : i'll check the link you sent me and then i'll keep you in touch. And yes i'll review the backing up subject :)

Actually i tried to start with bruteforce-luks-masrer but i don't get it to install (on linux).

Bernard
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    If you do try the bruteforce-luks, please tell us how many pass/sec you did and what cpu/graphics card you have. – Manumit May 24 '15 at 19:13
  • When you get access to your data, make sure to set up proper, regular backups. Your data is still there, so at least in theory, you should be able to gain access to it, given time; but what if the problem had instead been a hard disk crash? Such things happen all the time. – user May 24 '15 at 20:04
  • Thank you. How do i know if it was a hard disk crash? And how i recover the password, please? – Bernard May 24 '15 at 21:07

2 Answers2

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Well given you once knew the password and assuming it should be a variation of a previously known password use of a password list and a tool such as https://github.com/glv2/bruteforce-luks it should be relatively easy to recover.

On that note, to prevent this scenario I the future you may want to review the process for backing up keys and the metadata used on the disk.

jas-
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From what I'm reading on the net, cracking LUKS is going to be a SLOW process.

Consider this scenario: I forgot half my 13 chararacter (complex) password on truecrypt. But even with this information... I KNEW it was 13 characters long, I knew half the pass, I had professional software attempting 2000 passwords per second. And yet it took me 20+ hours to crack if I remember correctly. LUKS will be a lot slower to crack, I assume.

Now consider your scenario, how long is your password, what do you remember, and most importantly how complex is your p4S$w0rD? if you got the faith so far, you also need to consider if you are getting help or if you go the cracking route yourself.

edit: in a 2014 article they are bragging about doing 300 pass/sec on LUKS. They are bragging. I'd say bruteforcing (guessing every possible comination of what you can't remember) is out of the picture. If you go the cracking route, free software will probably be even slower, but its worth a try if your pass is simple.

Manumit
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    150M passwords tried, out of something like 450bn possibilities? (Upper/lower case + digits, 13/2=6.5 characters unknown.) If anything, that shows how much can be gained in terms of brute-force speed if some information about the password is known. – user May 24 '15 at 20:02
  • My 1500$ (CPU+graphics card) rig did 2k pass/sec on truecrypt volume - passware goes bragging online that they can do 300/sec on LUKS with god knows how expensive "home" rig. – Manumit May 24 '15 at 23:26
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    Also LUKS unlocking time can be influenced by tweaking the number of iterations. I do 1pass/min on my server's drives. I'd better not lose the password. – Xaqq May 24 '15 at 23:53
  • @Manumit If that was in response to my comment, I wasn't referring to the password trial throughput (X number of passwords per second) but rather how small a portion of the possible space (about 0.035%, assuming 62 possible characters and 6.5 unknown) needed to be searched before the password was found, let alone how small a portion of the total possible (given the password length and complexity) search space this was. This is something most people don't ever stop to consider; guessable passwords, or portions of passwords, make a massive dent in the difficulty in finding them. – user May 25 '15 at 07:33