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11

By default, Bitcoin Core creates 100 addresses the first time it starts, and tries to keep 100 not-yet-used keys in wallet.dat 'keypool' (when you unlock the wallet to make a payment it will generate more). So you do not need to backup continuously. The 'getinfo' RPC command will tell you the time when the oldest not-yet-used key was generated ('...


10

A wallet is a combination of private keys, and transactions that spend from/to it. Since somewhere in the 0.3 series, bitcoin will detect transactions from a key of yours that you did not create yourself, and count them as spends. This means that if you duplicate your wallet on several machines, they will all be able to do spends, and observe spends by ...


10

This is how you obtain the private key for an Armory wallet: In Armory-Qt, click on Wallet Properties (or in the newer versions, double click on your wallet to open your Wallet Properties), then click Backup this wallet>See other backup options>Export Key Lists then click the button Export Key Lists. Enter your passphrase and Armory will show your wallet's ...


9

You can't get your bitcoins with just the receiving address (if that could be done, they could easily be stolen), so your only chances of retrieving them are: If they're stored in the wallet file you have backed up, then you can use that Somehow recovering the original wallet file, which is a data recovery exercise. This might be possible in the case of a ...


8

For Mycelium, the actual file that contains the encrypted keys are in the sqlite3 file. You can see in the source code that though there is in-memory storage, it's used mostly for testing and that the main way in which Mycelium data is stored is in a sqlite3 file. Sqlite, if you aren't familiar, is a very simple relational database that contains the whole ...


8

It is important to be able to recover your private keys using only tools you fully control. That protects you against failure of infrastructure you would otherwise need to transfer your funds. There are lots of stories of corrupted backups, unreadable backups, and backups that didn't actually include the private keys. Storing your private keys unencrypted ...


7

bitcoin-qt open the File menu click Backup Wallet... select a file to save the backup as MultiBit From http://multibit.org/help_backupWalletUsingPrivateKeys.html: You can export your private keys from a MultiBit wallet into a file (using the 'Tools | Export private keys' option) and, as long as you do not manually create new receiving addresses, ...


7

Knowing your private and public keys is enough to be a backup of that address. If you only have one address all you would have to do is create a new wallet and import that private key. Why backup the entire wallet.dat then? Because restoring the wallet.dat saves you the step of importing the keys from the command line. Most people find it easier to backup ...


7

Right now, that's not supported. You can try (see user2194702's answer), but if you don't know the exact workings of the wallet, you're very likely to shoot yourself in the foot. For example, Bitcoin-Qt will send change to a new address every time you create a transaction, and in general does not follow the "balance per address" concept but a "balance per ...


6

It sounds like you have an old wallet backup that does not have the private key to the public address you are looking for. You are probably in the realm of data recovery. I wrote a blog article that might help: http://gary-rowe.com/agilestack/2012/08/17/how-to-recover-your-bitcoins-from-a-failed-hard-drive/


6

Run the client with the parameter -keypool=10000 to generate 10000 keys in your keypool. Pros: Less backing up Cons: Your wallet will be bigger (file size) and take maybe a few seconds extra to load


6

The Bitcoin-Qt/bitcoind client's keypool has by default 100 Bitcoin addresses. Each spend transaction that has change chews up one of those addresses. Additionally each click on New Address will consume an address from the keypool as well. So you should be able to get by without a new backup until after 100 spend transactions plus any requests for a New ...


6

Yes. Yes. No. Note that that the software's encryption encrypts only the private keys, not transaction and address book information, so to protect your privacy you may want to add encrypting the file itself.


5

A wallet (by default) always contains 100 unused keys. Every time the client needs a new key (for a new address, for sending change to, or - in theory - for solo mining payouts), it takes the oldest address from the pool, and creates a fresh one to add. This just means you need to backup every 100 transactions. No need to switch to a new wallet.


5

Mt. Gox operates a hosted (shared) EWallet. They claim to have cold storage and perform other backup practices, but there is nothing that you as a Mt. Gox accountholder can do to "back up" those funds. And if there is a problem restricting you from accessing your Mt. Gox account, there is nothing you can do to recover those funds. If you have your own ...


5

Since 0.6.0, key import/export are available in the client itself, though only through RPC. The commands are called dumpprivkey and importprivkey. For example (on testnet): $ ./bitcoind getnewaddress n2JjZgLeCUgfubswxDm9zAaBGSLLHSLdNv $ ./bitcoind dumpprivkey n2JjZgLeCUgfubswxDm9zAaBGSLLHSLdNv ...


5

To answer the part about the stolen wallet, the thief would immediately transfer the balance of your stolen wallet into his own wallet, and repeat the process regularly. So whenever you added more Bitcoins to your wallet, they would vanish as the thief stole them. So you would be able to share the stolen wallet with the thief, but it would be a very ...


5

Since wallet.dat is mostly a collection of private keys, you will simply lose all private keys that you have not duplicated or copied. It also by default stores the next 100 Bitcoin addresses it will give you when you generate a new address as a safety measure. Bottom line You will lose the copy of the private keys to addresses you've created or added but ...


5

You are correct. However, in all open source wallets that follow the proper Bitcoin Improvement Proposals (BIPs) people will be able to replicate the encryption logic so you can use your passphrase to get access to your private keys again. Still, I would recommend, for the majority of your bitcoins, to store them to a paper wallet with the private key ...


4

Piuk has just made a patch to MultiBit that enables blockchain.info 'json' and 'aes.json' files to be imported. This patch was included in MultiBit 0.3.4. Here is the how-to: Export wallet from blockchain.info -> Import to MultiBit 1) Do a wallet export from blockchain.info 2) Import into MultiBit using the 'Import private keys' screen. 2.1) In the ...


4

You do not need to send coin to another wallet, but you surely need them to be sent to another address (since the compromised wallet has compromised addres). What I would is go to http://blockchain.info and open a new wallet. Copy paste the first address you see, it'll be your new secure address since you just genereted it. Then import your old compromised ...


4

Assuming you had a chance to send those transaction out, they will still be processed. So long as the transactions didn't create any new change addresses, your wallet will still have all the information needed to spend any Bitcoins you have left.


4

If you made more than 100 transactions and individual receiving addresses combined, yes. Best way to find out is to try.


4

I'll go through your question clause by clause: I've made an offline address You're doing good. and only have the key stored on 2 encrypted flash drives stored in different locations As long as only you know the password and the password is sufficiently strong, this is probably secure. with the private key written physically on paper and stored ...


4

Blockchain.info has two separate "mnemonics", one for each password (using that term loosely, since it's not the type of permanent mnemonic every other mnemonic-capable wallet uses). I agree they don't make it at all clear that you gain a second one once you add a second password. It sounds like you only have the main one. If you have completely forgotten ...


4

Restoring a wallet on a fresh machine: Start Bitcoin-Core (daemon or Qt), shut it down after it has started up (you only do that to create the necessary data directory) Replace wallet.dat with your backed-up wallet.dat (see https://en.bitcoin.it/wiki/Data_directory if you can't find the data dir) Startup Bitcoin-Core, wait until your node is in sync (can ...


4

Using words to back up wallets is a process described in BIP 39. Basically, the mnemonic is converted into a seed. This seed is then used as the seed to a Heirarchical Deterministic (HD) wallet, as laid out in BIP 32. The seed is used to generate a Master Extended Private Key, from which all other private keys can be generated. The child key generation ...


3

When you generate new accounts inside a wallet you will only have to make a back-up once. The backup key gives armory the possibility to create a indefinite series of addresses for your wallet. Please note that by default, Armory only generates 100 addresses. This means that when you use more than 100 and you lose your wallet, after you restore the back-up, ...


3

This should work just fine, for the most part, though it's not recommended. What would not be fine is multiple PCs accessing the same wallet.dat from, say, dropbox at the same time. The BerkeleyDB format Bitcoin uses for its wallet is not intended to be a multi-user database and as such this can cause problems if both systems attempt an action at the same ...


3

Make sure to delete wallet.dat - that's the only file with sensitive information. (You might want to run a utility such as unix shred on it to make sure it's really deleted). Just a warning - before deleting, rename the file, and try to copy it from your backup and see if everything works.


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