Use ASIC to brute force wallet.dat? Possible?

[spooderman]

So my friend forgot his wallet password. Genius. 25 characters long, but something's not right. Tried a few hundred combos manually.

Question is,

Can I use my BFL 6.5GHz miner to crack it? How "S" are these "ASICs"?

It's checking hashes of sha 256 anyway right? Is it just down to software?

Thanks in advance.

22.1btc in the wallet.

2.2 BTC to anyone who sorts this for me.

edit: if we crack it that is! it's gonna come from his stash not mine! Let me get the address so you know where it's coming from...

edit 2: we know for certain what MOST of the password is. This is a typing error, not a completely loss of the password.

[spooderman]

here is the wallet file your reward will come from https://blockchain.info/address/15sZVJHZ8mSL29My2hsBN1njSivuQUPxn6

as you can see the coins have been stuck for ages and if I move them for him you will be able to see.....

No scams 'ere!

[OnkelPaul]

ASICs are just for computing block header hashes. They don't work at all on wallet passwords.
I suppose it's a password protected bitcoin-qt wallet?
A GPU wallet password cracker might help, but I don't have any experience with that.

Onkel Paul

[DannyHamilton]

A 25 character password that you know nothing about?  Sorry, but you're not going to brute force that.

Now, if you can narrow down the range of possible passwords enough, then you might be able to brute force what's left.

Is there ANYTHING at all that your "friend" remembers about his password?

Was it likely to include any upper case letters?
Was it likely to be all upper case letters?
Any estimation of how many upper case letters it was likely to have?

Was it likely to include any lower case letters?
Was it likely to be all lowercase letters?
Any estimation of how many lower case letters it was likely to have?

Was it likely to include any numbers?
Was it likely to be all numbers?
Any estimation of how many numbers it was likely to have?

Was it likely to include any special characters (such as spaces or punctuation)?
Was it likely to be all special characters?
Any estimation of how many special characters it was likely to have?

Was it likely to contain any real words?
Was it likely to be all real words?
Any estimation of how many real words it was likely to have?
Any estimation of how many letters long those real words would be?

Was it likely to include any names?
Was it likely to contain any dates?
Was it likely to contain any misspelled words?

Was it likely to contain words with replaced letters (such as 3l3ph@nt instead of elephant)?
If so, what substitutions does your "friend" typically make?

The more details your friend can remember about how they would have come up with a 25 character password, the better your chances of being able to brute force it.

[spooderman]

Apologies we know LOTS about the password. We SHOULD know 24 of the characters. He wrote a cryptic clue for what it was and emailed it to himself. We definitely DON'T know one of the characters. We tried about 100 different password manually, trying every possible character on the keyboard and none of them work.

This means that one (or more) of the other 24 is wrong.

Thanks for contributing Danny, I've been reading your posts for years and you've been an excellent help to people before

[spooderman]

ASICs are just for computing block header hashes. They don't work at all on wallet passwords.
I suppose it's a password protected bitcoin-qt wallet?
A GPU wallet password cracker might help, but I don't have any experience with that.

Onkel Paul

Thank you for the help.

[DannyHamilton]

Search around the forum a bit.

There are programs that people have provided that will allow you to provide the information that you are sure about, and it will try all the possibilities of the information that you are not sure about.

You might also get someone to write a custom program specifically for your problem if necessary.

It sounds like you have a 25 character password that is mostly correct?

That 25 character password has 1 character that you know is wrong, and you know which character it is?
That 25 character password might have an additional character that is wrong, but if so you don't know which character it is?

So, 1 character with 95 possibilities to try with each of
24 remaining characters with 95 possibilities

If I've got my math right, that's about 216600 possible passwords.

That's more than you're going to want to try manually, but a computer should be able to churn through it pretty quickly without needing any special GPU or ASIC programming.

[spooderman]

Search around the forum a bit.

There are programs that people have provided that will allow you to provide the information that you are sure about, and it will try all the possibilities of the information that you are not sure about.

You might also get someone to write a custom program specifically for your problem if necessary.

It sounds like you have a 25 character password that is mostly correct?

That 25 character password has 1 character that you know is wrong, and you know which character it is?
That 25 character password might have an additional character that is wrong, but if so you don't know which character it is?

So, 1 character with 95 possibilities to try with each of
24 remaining characters with 95 possibilities

If I've got my math right, that's about 216600 possible passwords.

That's more than you're going to want to try manually, but a computer should be able to churn through it pretty quickly without needing any special GPU or ASIC programming.

Thanks very much. I helped another friend a while ago (you feel obligated when you convinced them to buy in the first place) but had to get a friend to write a program, and he cracked it. But he's got no time to help me at the moment and won't for a long time.

Your understanding of the situation is correct (character 21 is wrong for sure, and another random character is probably also wrong). I'm guessing you got the maths right.

I have looked around the forums and found people that have written programs but I had little luck trying to work out how to use them.

Hence the bounty.

[MCHouston]

Your best bet is to sign up for Amazon AWS and rent a compute node probably cost you $20/month or so. As 95% of peoples home computers are too slow to do this in a decent time.  You will want something with lots of CPU and just decent RAM with small disk space. Use the spot instances so you pay alot less then on demond prices.

Then you will use linux based cracking software that can be found on the internet.

You will fill in the part of the passwords you know for sure and which ones you dont.  The server will try all combinations depending how much it has fill in could take 10 min could take a couple months but it will get it eventually assuming you have most of the password already and it is not crazy long.

[DannyHamilton]

Your best bet is to sign up for Amazon AWS and rent a compute node probably cost you $20/month or so. As 95% of peoples home computers are too slow to do this in a decent time.

216,600 possibilities?

Even on a very slow computer that can only try 1 password per second, that's still only 60 hours to try every possibility.  Renting computing power from Amazon AWS would be a waste of time and money for this situation.  Heck, even if the computer could only try one password every 10 seconds, that's still only 600 hours (about 25 days).

[spooderman]

Your best bet is to sign up for Amazon AWS and rent a compute node probably cost you $20/month or so. As 95% of peoples home computers are too slow to do this in a decent time.

216,600 possibilities?

Even on a very slow computer that can only try 1 password per second, that's still only 60 hours to try every possibility.  Renting computing power from Amazon AWS would be a waste of time and money for this situation.  Heck, even if the computer could only try one password every 10 seconds, that's still only 600 hours (about 25 days).

My friend cracked my other friend's lost password on a laptop, took 90 minutes and he tried 5 million passwords I think.

[shorena]

I tried to bruteforce a wallet for someone in the past and I wont do it again any time soon.

Some threads/links that might help:

- http://www.walletrecoveryservices.com/ - service
- https://bitcointalk.org/index.php?topic=717334.0 - service
- https://bitcointalk.org/index.php?topic=85495.0 - possible service, ruby scripts (IIRC), etc.

[guitarplinker]

I assume you found the password? All funds were moved from that wallet on the 14th.