Redeem private key bitcoin wikipedia
However address reuse is very bad for privacy and security. Because of this, one is forced to choose between hazardous options:. Therefore, it is highly recommended that you use proper paper wallets which allow you to generate an infinite number of addresses from a single seed.
Proper, multi-key paper wallets usually take the form of a multi-word HD wallet seed mnemonic. The list of several words corresponds to some binary data that is used to generate all of the addresses. Words are used to make it easier to avoid and correct errors. Trying to memorize an entire seed mnemonic is very difficult and is generally not recommended.
A single key for use in insecure single-key paper wallets or redeemable codes can be represented in several formats, but typically the Wallet Import Format WIF is used, since keys represented that way are very short 51 characters and thus easy to re-enter when importing or "sweeping" it for withdrawal. The private seed is used to prove your right to spend the bitcoins transferred to the paper wallet, and as such should be kept hidden and secret.
If the private seed on a paper wallet is exposed for example in a photograph then the wallet may be used by anyone who sees it. To guard against accidental revelation, the private key displayed on the paper wallet may be encrypted or split into several different parts for example using Shamir's secret sharing scheme.
At the very least, the private key should be well hidden e. Currently, at least Armory and Electrum support generating mnemonic codes for their wallets, which can be written down or printed to make a multi-key paper wallet. Several tools exist for producing single keys, including Bitcoin Address Utility , vanitygen , and Cwallet. Again, using single keys for anything except one-time transfers of bitcoins is strongly discouraged. Even with careful code auditing, browser plugins or other websites may compromise the environment.
Some advanced printers have internal storage even hard drives that preserve copies of printouts. This is a risk if someone gets access to your printer, or if you dispose of your printer. There is also the possibility that a smart enough printer can be hacked.
Consider StuxNet which was able to rewrite the firmware of non-computer devices indirectly connected to the Internet If this concerns you, use a "dumb" printer, and never let your printer have access to the Internet or to an Internet-connected computer.
An alternative using a printer for paper wallets is to write the private key and address with your own hand. Base58Check encoding used for Bitcoin addresses and private keys specifically excludes characters that look similar like 0OIl. The mnemonic recovery seeds used by wallets like Armory and Electrum are also suitable to be written by hand.
Paper keys, when used as wallets, are very different from wallets such as Bitcoin Core in that there is only one address in a paper key rather than a hundred or more online keys that are managed with full software assistance from Bitcoin Core.
Note that importing a private key that may be compromised can result in the entire wallet becoming insecure. For this reason, sweeping or sending the entire amount to a fresh address is generally recommended over plain importing.
Because paper wallets only record the private key and address, wallet software which redeems the bitcoins must somehow learn about the balance of the wallet before being able to spend it.
The solution with the best privacy properties is to import the private key into bitcoin-qt and rescanning. Nobody watching the bitcoin-qt full node from outside will be able to tell which address it's interested in because all the scanning happens locally on disk. Because the private key is the "ticket" that allows someone to spend bitcoins, it is important that these are kept secure. Private keys can be kept on computer files, but in some cases are also short enough that they can be printed on paper.
Some wallets allow private keys to be imported without generating any transactions while other wallets or services require that the private key be swept. When a private key is swept, a transaction is broadcast that sends the balance controlled by the private key to a new address in the wallet.
Just as with any other transaction, there is risk of swept transactions to be double-spending. In contrast, bitcoind provides a facility to import a private key without creating a sweep transaction.
This is considered very dangerous, and not intended to be used even by power users or experts except in very specific cases. Bitcoins can be easily stolen at any time, from a wallet which has imported an untrusted or otherwise insecure private key - this can include private keys generated offline and never seen by someone else [1] [2].
In Bitcoin, a private key is a bit number, which can be represented one of several ways. Here is a private key in hexadecimal - bits in hexadecimal is 32 bytes, or 64 characters in the range or A-F. Wallet software may use a BIP 32 seed to generate many private keys and corresponding public keys from a single secret value. This is called a hierarchical deterministic wallet , or HD wallet for short.
The seed value, or master extended key , consists of a bit private key and a bit chain code , for bits in total. The seed value should not be confused with the private keys used directly to sign Bitcoin transactions. Users are strongly advised to use HD wallets, for safety reasons: An HD wallet only needs to be backed up once typically using a mnemonic phrase ; thereafter in the future, that single backup can always deterministically regenerate the same private keys.
Therefore, it can safely recover all addresses, and all funds sent to those addresses. Non-HD wallets generate a new randomly-selected private key for each new address; therefore, if the wallet file is lost or damaged, the user will irretrievably lose all funds received to addresses generated after the most recent backup. When importing or sweeping ECDSA private keys, a shorter format known as wallet import format is often used, which offers a few advantages.
Wallet import format is the most common way to represent private keys in Bitcoin. For private keys associated with uncompressed public keys, they are 51 characters and always start with the number 5 on mainnet 9 on testnet. Private keys associated with compressed public keys are 52 characters and start with a capital L or K on mainnet c on testnet.
This is the same private key in mainnet wallet import format:.