Bitcoin-Qt where is my wallet
A private key in the context of Bitcoin is a secret number that allows bitcoins to be spent. Every Bitcoin address has a matching private key, which is saved in the wallet file of the person who owns the balance. The private key is mathematically related to the Bitcoin address, and is designed so that the Bitcoin address can be calculated from the private key, but importantly, the same cannot be done in reverse.
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 they are also short enough that they can be printed on paper. An example of a utility that allows extraction of private keys from your wallet file for printing purposes is pywallet.
In order to create a transaction with a private key, it must be available to a program or service that allows entry or importing of private keys. Some wallets allow the private key 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 entire balance held by the private key to another address in the wallet or securely controlled by the service in question.
An example of private key sweeping is the method used on MtGox’s Add Funds screen and BIPS Import screen. Just as with any other deposit, there is risk of double-spending so funds are deposited to the MtGox account after a six-confirmation wait (typically one hour). In contrastBlockChain.info’s My Wallet service and Bitcoin-QT each provide a facility to import a private key without creating a sweep transaction.
An example private key
In Bitcoin, a private key is a 256-bit number, which can be represented one of several ways. Here is a private key in hexadecimal – 256 bits in hexadecimal is 32 bytes, or 64 characters in the range 0-9 or A-F.
E9 87 3D 79 C6 D8 7D C0 FB 6A 57 78 63 33 89 F4 45 32 13 30 3D A6 1F 20 BD 67 FC 23 3A A3 32 62
