Are there Bitcoin password crackers I can use to recover forgotten passwords?

I've lost the password to one of my wallets (it's a small one, don't worry). I was sure I remembered the password ... but evidently I don't.

Is there a program that I can use to brute-force my password, given hints?

Meaning, suppose that I remember that my password was "abc", but in fact maybe it's "Abc" or "Abc0". I would give the cracker program the string "abc" as a hint, and it would try a lot of permutations on it until it finds the real password.

Does such a cracker program currently exist? (Reliable sources please, hopefully open source)

ripper234

Posted 2012-03-29T06:57:21.397

Reputation: 25 192

To clarify, are you asking about the Satoshi client? I have a 'mywallet' that I instantly forgot the password to, but I believe it's empty. – Chris Moore – 2012-03-29T08:45:17.130

1@ChrisMoore - yeah, Satoshi/standard client. – ripper234 – 2012-03-29T09:33:56.967

1If you don't want the password to exist anywhere outside your brain, you should use a spaced repetition software to memorize it. (Ideally the software should be able to check your input against a stored hash, and used on a computer permanently disconnected from the internet) – Meni Rosenfeld – 2012-03-29T10:45:57.290

3@MeniRosenfeld and what does this have to do with this question? – o0'. – 2012-03-29T12:19:27.420

3@Lohoris: That it proposes alternative solutions to its premise. I am under the impression that this is acceptable use for comments. – Meni Rosenfeld – 2012-03-29T12:57:39.050

I had to google "spaced repetition". Found http://en.wikipedia.org/wiki/Spaced_repetition and thought a link here might be useful.

– Chris Moore – 2012-03-29T16:24:33.103

3@Meni: At this point, the password does not exist anywhere outside his brain (and possibly no longer inside, either) :-) – Thilo – 2012-03-30T04:27:48.213

1@Thilo: Yes, but this circumstance can be prevented for the future, in theory at least. – Meni Rosenfeld – 2012-03-30T07:15:22.023

4FYI - luckily enough, the password was indeed stored on my Keepass. I just named the entry "wallet" and not "bitcoin", so when I searched for it it didn't come up. But the question is still relevant. – ripper234 – 2012-04-02T16:52:01.550

1Yeah!

+1 for KeePass! – Stephen Gornick – 2012-04-03T19:07:13.037

Yup, question is still relevant. Here's another unfortunate story: http://www.reddit.com/r/Bitcoin/comments/rqymz/forgot_my_walletdat_password_how_to_fix

– Stephen Gornick – 2012-04-03T19:07:51.493

Answers

Revalin made available a sript that you can try running:

http://bitcointalk.org/index.php?topic=85495.msg942171#msg942171

There may not yet be anything else, but you'ld probably find someone willing to write one if you offered to send your wallet along with what you think the pass phrase might be and ask only for a fraction of the wallet's bitcoins back once cracked.

Stephen Gornick

Posted 2012-03-29T06:57:21.397

Reputation: 26 118

1Make sure that the "someone" is trustworthy - at least if you want to get your coins back. – BinaryMage – 2012-03-29T23:28:11.050

5Depending on how wallet encryption works, you don't need to actually send the wallet itself, but only the header. – CodesInChaos – 2012-03-30T10:11:18.953

3Much better to ask that person to write a script for him, in exchange for a fixed amount. – o0'. – 2012-04-04T12:00:26.997

Another alternative is btcrecover, available on GitHub here. From the Tutorial:

btcrecover is a free and open source multithreaded wallet password recovery tool with support for Armory, Bitcoin Core (a.k.a. Bitcoin-Qt), MultiBit (Classic and HD), Electrum (1.x and 2.x), mSIGNA (CoinVault), Hive for OS X, Blockchain.info (v1 and v2 wallet formats, both main and second passwords), Bither, and Bitcoin & KNC Wallets for Android. It is designed for the case where you already know most of your password, but need assistance in trying different possible combinations.

It also supports seed recovery for deterministic wallets:

seedrecover.py is a Bitcoin seed recovery tool which can take a seed with one or more mistakes in it, and recover the correct seed if not too many mistakes have been made.

_{Full disclosure: I am the developer of btcrecover.}

Christopher Gurnee

Posted 2012-03-29T06:57:21.397

Reputation: 2 263

You should try walletrecoveryservices.com since that appears to do just what you want. (brute forces bitcoin wallet recovery if you forget your password, without being able to steal your bitcoins)

user5977

Posted 2012-03-29T06:57:21.397

Reputation: 41

For a free badge, read the "About" page near the search bar. Thanks and Welcome to StackExchange! – Devyn Collier Johnson – 2013-07-16T10:57:32.423

You might want to add some links to testimonials to this answer. I have heard good things about this service but it's a good idea to be sure about it before handing over your wallet. – D.H. - bitcoin.se – 2014-01-04T20:33:22.573