If all I have is a paper wallet (with an address and a key), how do I use it?

[szangvil]

Say a friend sells me a paper wallet, how can I make sure that the wallet has the balance printed on the paper? What online service or software can I use to import that wallet and start using it?

[windtilt]

Go to blockchain.info and you can search for a bitcoin address to check balance. To use it you can open a wallet there and import the private key.

[John (John K.)]

Go to blockchain.info and you can search for a bitcoin address to check balance. To use it you can open a wallet there and import the private key.

This.

[windtilt]

Oh. And make sure to also take advantage of 2 factor auth, dual passwords. Make sure you use their backups and try to keep these very secure. Look into their chrome extension. Large balances should be kept on paper.

[jabetizo]

also, make sure to send the whole balance to a new address that only you control (only you know its private key). until you do so, anyone that has the paper wallet's private key can spend its funds.

[Zeal0t]

also, make sure to send the whole balance to a new address that only you control (only you know its private key). until you do so, anyone that has the paper wallet's private key can spend its funds.

This should definitely be a must-do in this case.

[GerMG]

Go to blockchain.info and you can search for a bitcoin address to check balance. To use it you can open a wallet there and import the private key.

This.

and do it 2 factor

[Jasmin68k]

To extend a bit on the op's question:

The first post here

http://www.reddit.com/r/Bitcoin/comments/1bhffb/how_to_create_and_use_an_offlineonly_wallet/

explains pretty well how to set up an offline wallet incl. adding and sending funds.

Quoted from there:

How to create and use an offline-only wallet (paperwallet or brainwallet)

This can be confusing and nerve-wracking to do, if you have never done it before. This is what I have done:

The one-time operation of setting up an offline-only brainwallet/paperwallet:
1. put a new USB stick into computer A (online machine)
2. Go to https://www.bitaddress.org/bitaddress.org-v2.4-SHA1-1d5951f6a04dd5a287ac925da4e626870ee58d60.html
3. right click on the page and Save as.. -> Webpage, complete
4. Download this onto the USB stick as well: https://www.strongcoin.com/downloads/offlineTransaction.zip
5. remove the USB stick from the online computer, and put it into computer B (offline computer. For this, I just use a Raspberry Pi)
6. Open The bitaddress.org page on the offline machine, and go to the brain wallet tab.
7. Create an alphanumeric passphrase, which generates your public/private keypair.
8. Save the public key (your wallet's address) into a file on the USB stick, and call it publicKey.txt (or whatever you want)
9. Write down the passphrase that you used to generate the public/private keypair and put the paper in a safe, safe deposit box, treasure chest that you bury in your backyard, or wherever else you like (or, if you're sufficiently paranoid, just remember it)
DONE!

To add additional funds to the offline wallet:
1. Simply provide the passphrase generated public key that you saved on your usb stick as publicKey.txt to the sender.
That's It!

To make a purchase from the offline wallet:
1. Get the public key of the recipient
2. Go to http://blockexplorer.com/q/mytransactions/<your public key> to get the transaction history of your wallet
3. Copypaste the recipient's public key and your transaction history from the online computer onto the usb stick.
4. open the USB stick on the offline computer, and open the StrongCoin offlineTransaction page
5. open the bitaddress.org page on the offline computer and enter your passphrase to get your private key.
6. Fill in the offlineTransaction form with the transaction history of your public key that you copied from the online machine, and your private key that you just generated via your passphrase
7. click the Parse button on the form.
8. Specify the recipient's public key as the 'Target Address', and the Amount to send, and the fee, the click 'Generate' on the form.
9. Copypaste the generated raw transaction from the form, onto the usb stick on the offline computer as transaction.txt (or whatever you prefer).
10. Plug the usb stick back into the computer, and copypaste the contents of transaction.txt into http://blockchain.info/pushtx and click the 'Submit Transaction' button.
Transaction Complete!

[hidziugas]

Thanks for the info, I really needed that.

[503guy]

You can download the wallet client and use the console to import the private key.