This guide was written in 2014 but still is the best, safest, way to create a paper wallet. You can store your Bitcoin in a hardware wallet, but what if your house gets hit by lightning or floods? What if you store your coins on an exchange, and it gets hacked? Of course on paper, you may have a problem if you have a fire, but you can easily store a copy of the paper wallet in a second place, or buy a fireproof box.
Here it is:
Once you have more than 1 or 2 Bitcoins, you will probably want to store them on a paper wallet. To do this in a secure fashion, you will need the following items:
A new flash drive.
An online computer.
An offline computer.
An offline printer.
First go to www.bitaddress.org using your online computer. Bitaddress is an open source key generator. Make sure you have a secure connection by checking the URL bar.
It should look like this:
Make sure you can see https. That means you have a secure, encrypted, connection.
You can also verify that the code is not being spoofed. To do that, right click on the web page:
Then select View Page Source. The source code should have a SHA256 patch, that starts like this:
// The core
SHA256._sha256 = function (message) {
// Convert to byte array
if (message.constructor == String) message = UTF8.stringToBytes(message);
/* else, assume byte array already */
var m = util.bytesToWords(message),
l = message.length * 8,
H = [0x6A09E667, 0xBB67AE85, 0x3C6EF372, 0xA54FF53A,
0x510E527F, 0x9B05688C, 0x1F83D9AB, 0x5BE0CD19],
.
.
.
.etc....
If you're not sure what your looking for, and you don't trust the code, check with any decent html programmer.
One you are sure you have a safe connection, and are at the correct website, install the new flash drive into your online computer.
Click on your web browsers menu:
Once the file is saved, remove the flash drive from the computer immediately.
Next you need an offline computer.
The offline computer should be one that has never been online, will not be online in the future, and is virus/malware free. The best way to insure this is to take an old computer, erase the hard drive and reinstall the OS.
We purchased a complete computer from a Salavation Army store for $20.00, then installed a fresh copy of Windows 98 from a CD.
DO NOT connect the computer to the internet to allow updates. This computer should never be used online. You want this computer to remain "air locked".
Access the file on your flash drive, and click on the bitaddress.org file. The website should run like an application in offline mode. The URL bar should look like this:
Next click on the brain wallet tab:
Enter 50-60 Random characters in the passphrase box:
Click the view box, and the public and private keys will be generated:
Next you have the option of printing, or writing down the Bitcoin address and private key. Either way, you must store them securely. DO NOT copy the key and print it on your online computer. You must use the offline computer. You can also save a copy of the key on your flash drive, but NEVER put the flash drive back into an online computer.
Before you transfer any Bitcoin to the public address, double check that your new private key has never been used. Go to www.blockchain.info and type the public key into the search bar:
The results should look like this, the wallet should be empty:
You are now ready to transfer Bitcoin to your offline wallet. First transfer a small amount of coin to the public address. Try .001BTC. Once that works, you can transfer larger amounts.