user78: 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)

user5977: 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)

user25088: 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.

user153: 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.

78: <p>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.</p>

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

<p>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.</p>

<p>Does such a cracker program currently exist? (Reliable sources please, hopefully open source)</p>
 5977: <p>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)</p>
 25088: <p>Another alternative is btcrecover, available <a href="https://github.com/gurnec/btcrecover#btcrecover--" rel="noreferrer">on GitHub here</a>. From <a href="https://github.com/gurnec/btcrecover/blob/master/TUTORIAL.md#btcrecover-tutorial" rel="noreferrer">the Tutorial</a>:</p>

<blockquote>
  <p>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 &amp; 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.</p>
</blockquote>

<p>It also supports <a href="https://github.com/gurnec/btcrecover/blob/master/docs/Seedrecover_Quick_Start_Guide.md#seedrecoverpy" rel="noreferrer">seed recovery</a> for deterministic wallets:</p>

<blockquote>
  <p>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.</p>
</blockquote>

<p><sub>Full disclosure: I am the developer of btcrecover.</sub></p>
 153: <p>Revalin made available a sript that you can try running:</p>

<ul>
<li><a href="http://bitcointalk.org/index.php?topic=85495.msg942171#msg942171" rel="noreferrer">http://bitcointalk.org/index.php?topic=85495.msg942171#msg942171</a></li>
</ul>

<p>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.</p>
