For those of you looking to import your Vanity address, hacked key or paper wallet into your Bitcoin QT client, here are the instructions:
- Backup Your Wallet. Although this process is well tested and used you should always take another backup of your wallet.dat file before starting.
- Then select Debug Window -> Console
- Unlock your wallet. If your wallet is encrypted you must unlock it. Unlock it by entering walletpassphrase "YourLongPassphrase" 600next to the > input box. If wallet is not locked just skip this step.
- Next to the > input box type importprivkey <bitcoinprivkey> 'OptionalLabel' (Note that the private key must not have spaces, remove them if they are included in your backup)
Example: importprivkey 5KJvsngHeMpm884wtkJNzQGaCErckhHJBGFsvd3VyK5qMZXj3hS
The label may have spaces, the quotes are only needed if you want a space in the label.
On a fast PC it takes 2 minutes to import, and during this time it looks like you application has hung. You are now done.
While adding multiple keys you may want to avoid a time consuming rescan after each key. To do so use the command importprivkey <bitcoinprivkey> '' false for each key and importprivkey <bitcoinprivkey> '' true for the last one. The blank label is needed to pass the true/false flag.