Quote from: Nightshader on November 23, 2013, 08:13:24 PM

In respect of opening up my account here I like to share some things learned over the last few days.

Got some Bitcoins in my wallet, how to cold store them on paper?

I already made some backups of the wallet.dat the bitcoin-qt (original) client uses to store my wallet. But that didn't feel good knowing that this one file could be brute-forced to open the pass-phrase. So after some research the conclusion was: Just knowing the uncompressed private key of the wallet is the only thing needed to store securely on paper ( given the private key only, one can calculate the public Bitcoin address and the blockchain knows the number of btc on this address and stores it forever ).

What I practically did:

Extracted the real uncompressed private key so I'am independent of the clients backup format
Using Bitcoin-qt go the Help menu and Enable the Debug window
Use the command: walletpassphrase "yourpassword" 600
Now your locked/encrypted wallet has been opened for private commands
Use the command:dumpprivkey yourbitcoinaddress
Now you see something like 91b24bf9f5288532960ac687abb035127b1d28a5
Offline created QRcodes containing the private key and the Bitcoin address using http://sourceforge.net/projects/qrcodegenerator/files/code/
Without storing on media directly print two copies of the QRcodes and in plaintext to avoid any QRcode reading problems in the future - who knows

This is bad advice that is a good way to lose Bitcoins. If you are advocating this for:

backing up your wallet: The balance of your bitcoins may not be in the address you see, and the entire contents of one address may be emptied by just one small transfer.
paper wallet: The whole point is to generate a can't-be-hacked wallet. You've made one on your computer in the way everyone expects you have, leaving data behind on that machine or a log of your activity if you've been hacked and have a key and screen recording trojan horse.

If you are attempting to make a backup of a wallet, there is a backup wallet option in the menu of Bitcoin-Qt.