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 ('...
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 ...
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 ...
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 ...
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 ...
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 ...
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 ...
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/
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 ...
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.
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.
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 ...
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.
You will lose the copy of the private keys to addresses you've created or added but ...
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 ...
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 ...
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.
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 ...
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 ...
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 ...
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 ...
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.
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, ...
(I suppose you have the Bitcoin-Qt client.)
Taking a backup of the Bitcoin folder will do it.
Copy the folder to an external hard drive of a different partition.
Reinstall your system.
Install Bitcoin-Qt again.
Move the folder back.
Note that to keep your bitcoins, only the wallet.dat file is required. But when you copy the whole folder, you will ...
1 Yes if you use that wallet only to keep coins but you don't use it to pay.
2 Same as answer nº 1
Trying to keep transactions difficult to trace, whenever you transfer bitcoins a second transaction is placed. That transaction moves a small amount to a new address created in your wallet. I don't remember how many "wallets" within your wallet are ...
TL;DR: If you have a frequent recurring backup you are safe, otherwise use a deterministic wallet.
No, you are not safe in that scenario.
Let me rephrase that, you are not safe if you really want to use your the coins from your addresses.
Wallet.dat file stores all public and private keys of your current addresses but standard client generates a new ...
I've looked at Bitcoin's backupwallet code, and that error is triggered by a filesystem error. I can't tell what kind of filesystem error it is, though. Please open debug.log in the Bitcoin directory. There should be a line like
<date + time> error copying wallet.dat to <path> - <kind of error>
This is the most common type of error:
Yes, it is completely safe to exclude the blocks directory from your backup process.
In the event that you lose all your files and need to restore from backup, Bitcoin will download all missing blocks. This may take some time, but there is no information in that directory that is unique to you.
Points for Hot Wallet Inheritability:
Lower exposure to risks - use hot wallets that are BIP 39 compliant and share your 12 to 24 recovery passphrase and associated password in advance.
Higher exposure to risk - share passwords on your devices that have hot wallets. BIP 32 compliant wallets make it easy to have the same logical wallet deployed on to ...