If I want to transfer an address from the satoshi client into a different client, how can I find its private key to do so?
To export a private key from your Satoshi bitcoin-qt client:
- launch your bitcoin client as usual and wait for it to load the blockchain and start up
- click on 'help' in the menu bar (top right)
- click on 'debug window'
- select the 'console' tab
- type: walletpassphrase "your walletpassphrase here" 600
- type: dumpprivkey [your Bitcoin address here]
- this will return the private key, you can copy it now; ensure you clear your clipboard/history afterwards
- type: walletlock
Note: Recent versions of the satoshi client offer a 'debug window' which can be used to export private keys. This is described in Miguel Moreno's answer to this question, and is easier than the steps I describe below.
To export a private key from your satoshi client:
bitcoin-qt -serverand wait for it to load the blockchain and start up
if your wallet is encrypted, run:
read -s x; bitcoin-cli walletpassphrase "$x" 600; unset xto unlock it for 600 seconds (type your passphrase after hitting return, then hit return again; this 'read; ...; unset' prevents the password being written to your shell's history file on disk, and the '-s' in read prevents your password being displayed as you type it, and improves protection from screen-loggers and the shell log)
run this command using bitcoin-cli:
bitcoin-cli dumpprivkey 1my1bitcoin1addres11111(replace 1my... with the bitcoin address of which you want the private key)
if your wallet is encrypted and you want to re-lock your wallet, run