9

The simplest and most common way of doing this is to do SHA256(passphrase) and to use the result as your private key. You can e.g. use the "Brain wallet" tab on www.bitaddress.org which is all javascript so that you can download it and do everything offline for increased security. Be aware though that your pass phrase must be really long and truly unique ...


5

I don't know if this is the recommended way, but I did this by using the Send Nxt API call on an offline computer, storing the transaction bytes, and broadcasting the transaction from an online computer by using the Broadcast Transaction API call.


5

If you have encrypted your Bitcoin.org wallet with a passphrase, then only having that passphrase will allow that to be decrypted. If you have a backup of your wallet prior to performing the encryption step, then any coins from that wallet that still have not been spent can be recovered. Otherwise, without that passphase to open the wallet you cant get to ...


5

The chances of someone "brute-forcing" or guessing your seed is extremely slim. There are more than 5 duodecillion possible combinations of twelve-word seeds. Just so you get an idea of how big that number is, it's more than 1 thousand million million million million million million possibilities.


4

The Bitcoin.org client does not yet have the feature to remove encryption from a wallet. You can use a single space as the encryption key but there no way to get it to no longer use encryption. That is expected to be implemented in a future release. In the meantime, those that want this will create a new wallet and leave it unencrypted, and send their ...


4

While the question isn't an exact duplicate, the answer essentially is, so I'm going to quote this answer by Pieter Wuille: As is normal when doing Elliptic Curve encryption, a private key is simply a random number. In the case of secp256k1, the elliptic curve used by Bitcoin, it has to be a number between 1 and ...


4

A very, very long time. Oxford English Dictionary contains full entries for 171,476 words in current use. If you use only lower case letters and they are mostly random words (no phrases - "four score and seven years ago" is like having your password be "secret"), there are about 7.47e41 possibilities. At 50 million attempts per second, it'll be about 4....


4

The passphrase is stored as part of the wallet.dat file, so yes, that should work, as long as you haven't received any payments to addresses with private keys that don't exist in the old wallet. Note that these received payments can actually occur when you send a payment, as a hidden "change" amount is sent to an unused hidden private key which is stored ...


4

Electrum uses AES-256-CBC to encrypt wallets. The key is sha256(sha256("your password")). Electrum wallet source: https://github.com/spesmilo/electrum/blob/master/lib/wallet.py slowaes library: https://code.google.com/p/slowaes/source/browse/trunk/python/aes.py


4

There is a script provided by a forum user Revalin which can be used to attempt variations. There is a forum user Rix who may be available for hire to provide assistance with this type of problem. You can also try out this script: https://bitcointalk.org/index.php?topic=170694.0


4

Is this considered safe enough? Nothing is "safe enough" if we do not know the cost. OK, if you have $100k in bitcoins the 12-words phrase is safe enough. If the 12-words phrase is the seed to the "Method of destroying the Universe" I would recommend to add at least 11 bits of entropy and use 13 words.


4

If your passphrase contains spaces or special characters, you will need to wrap it with single quotes (') so that the debug console can properly parse your passphrase. For example, if your passphrase were This is my passphrase, then your command should be walletpassphrase 'This is my passphrase'


4

Is there a way to just manually transfer the btc from the old wallet into a new wallet we do have access to No. You need at least one of the things you have none of working wallet. PIN or password for the wallet. Recovery phrase for the wallet. is there any way to extract the password or private keys directly from the wallet file? No. The brute-...


3

Multibit will prompt you for a password regardless of whether you are sending it to your own wallet or not. This is by design, since if it didn't do this, it would allow anyone who can access your laptop to transfer bitcoins from your encrypted wallet by sending it to the unencrypted wallet first. Sorry but unless you made an unencrypted backup of the ...


3

If your wallet hasn't been compromised (how can you be sure?) then it should be enough to secure it with a strong passphrase and then be sure to back it up. If your wallet has been or even just might have been compromised then securing it with a strong passphrase now might not be enough. Sending the Bitcoins at risk to a new address in the same wallet ...


3

The wallet actually uses a randomly generated master key to encrypt the keys, and this master key is encrypted using your passphrase. When you change the passphrase, all that changes is the encrypted master key. The actually encrypted wallet keys aren't touched at all.


3

Bitcoin-qt only asks for your password when you do an operation that requires it, such as sending coins. Currently, wallet.dat must be called that and reside in the Bitcoin data directory. It might be possible to use symlinks to work around that.


3

You can dump your old wallet to a backup file, restart the program to generate a new wallet and import your old wallet into it. Assuming you are in the directory where your wallet file is located, using the command line that would look like this: bitcoind walletpassphrase "xxx" 60 bitcoind dumpwallet "wallet.dat.backup" bitcoind stop mv wallet.dat wallet....


3

Yes. It is possible. Either the UI supports it or it does not. You are better equipped to find out than I am but I suspect it does not (yet). If it does not you can either: Export the keys, move the wallet files (rather than deleting it, so you can move it back if things to wrong, on Mac the wallet files are here: ~/Library/Application Support/Bitcoin/), ...


3

In particular, is there a way to make it so that it is impossible to know if a transaction signed with a password is correct unless its part of a mined block? This way, even if your password only requires 1,000,000 tries to crack, the attacker needs to mine 1,000,000 blocks to bruteforce the password? I'm not aware of any cryptographic constructions that ...


2

You ought to look into solutions such as Brainwallet. It hashes your passphrase into a Bitcoin address.


2

Blockchain.info does not use 2FA for encrypting the wallet and instead uses it only for limiting access via the web interface. If your system is compromised with a keylogger, and the attacker has access to the blockchain.info wallet (e.g., the backups sent via e-mail), for instance, then the attacker can perform a replay attack and spend the funds from the ...


2

It is all a matter of how many bits of entropy your passphrase has (how hard it would be to guess). Using a couple words provides a lot more randomness than a couple random characters. As far as I remember, the algorithm used to encrypt the private keys that is used by BitcoinQT has about 100 bits of security (which is a lot). You would want to attain a ...


2

No, because the encrypted keys don't change in that case. When you encrypt a wallet.dat file, a random master key is generated, the master key is encrypted using your passphrase, and the actual address keys are encrypted using the master key. When you change the passphrase, only the encrypted master key is changed.


2

Yes, any person you give your rpcpass and rpcuser to can control your wallet, that's not what the wallet encryption password designed to protect against. You really don't want to be giving arbitrary users your RPC authentication details under any circumstance, and I can't think of one where you would need to.


2

However, have never had the option of providing a passphrase. You must certainly have set a passphrase in the past. There's no way to remove it without knowing exactly what it is. If you can not recall what password you set, your funds are lost.


2

The wallet passphrase is there to protect the wallet file on disk. It is not an authentication mechanism or a security measure against anyone who can see what is sent to it. It does however prevent private keys from hitting disk in readable form.


2

That is certainly weird and it's most likely that you simply are typing a different password. To test this hypothesis, install MultiBit on another computer and import your wallet to see if it works. Perhaps your local MultiBit instance is corrupted. Another option would be to try different versions of the client, although the wallet encryption algorithm ...


2

There is a copy of the password stored encrypted with an AES key derived from the wallet words. Thus if you forget your password and still have a copy of your wallet you can use your wallet words to recover your password.


2

So just like Nick said, If the encryption is done using 256 bits then creating a passphrase which is 512 bits long would be the same as creating a passphrase which is 256 bits long (as long as its random). You should look into brainwallets as they provide a way to create strong passwords which are also easily memorable since all you have to memorize is a 3 ...


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