Install bitcoin wallet on usb
This makes sure that any funds in this wallet are part of your global balance. Now that the wallets are setup, you can use the watching-only wallet exactly the same way as a regular wallet, except Bitcoins cannot be sent from it. Use the Receive Bitcoins button to generate addresses for receiving payments, and incoming transactions will show up in the ledger with a slightly different color than your other wallets. On the online computer, click the Offline Transactions button on the right, below the logo.
Select Create New Offline Transaction. A window will open with the unsigned version of the transaction. Load the file from the USB key, then press the Sign button. A confirmation window will appear. Verify the confirmation details before you sign it! Click Save to file…. Eject the USB key and plug it into the online computer. If the original window is still open, you can click on Next Step to get to the broadcast window. If you closed Armory since then, you can use the same Offline Transactions button on the main window, and select Sign or Broadcast Transaction.
Once the file is loaded, some green text should appear telling you that the signature is valid and the Ready to Broadcast! Guidance is given at each step within the Armory software, so you may be fine without referring back to this page. And once you do this a few times, it will become a breeze! At no point in this process is any private data exposed through the transaction data. It is perfectly safe to transfer the signed or unsigned transaction via email.
The biggest threat to an offline wallet is a USB-key virus that executes when plugged in. However, such viruses would have to be highly targeted, and can be mostly mitigated by disabling USB-auto-run on the offline computer. So, how do you calm your nerves about using such advanced features?
Try it out with small amounts of Bitcoins. Whether it takes you a day or a year, you will eventually come to realize that offline transactions really do work.
Make a new wallet as described above, but you must make a backup. A digital backup is fine if you make a couple copies, just in case one becomes corrupted. Generate some addresses by clicking on Receive Bitcoins a few times. Write down the first few letters of each address generated. Why did we just delete it? If you can restore the backup once, you can always restore the backup at any time in future. On the main Armory window, click on Import Wallet in the upper-right corner, and select the type of backup you are restoring.
Generate some addresses with the new wallet. The cold wallet is created by running Bitcoin Core in an offline Tails session. Once created, keep the wallet cold - never enter the passphrase within anything other than an offline Tails or similar session. You will also need the Bitcoin Core binaries, which you can get here. On a modern computer and decent USB drive I find it stable, quick-booting and responsive. The first time you boot into Tails, create an encrypted persistent storage partition on the USB drive - this is straightforward, just follow the instructions here.
KeePassX is actually bundled with Tails. Boot into your Tails USB disk. At this point, Bitcoin Core will have created two receiving addresses that are managed by the wallet. Access these addresses via the Bitcoin Core File menu:. Two unnamed accounts are created by default during wallet setup. The API still has lots of references to accounts - for example, to list out addresses, the getaddressesbyaccount method is required.
If you were to send funds to a public address controlled by this wallet, they would be irretrievable. You can open a wallet by passing in the -wallet option when opening Bitcoin Core - BUT the wallet must be located in the Bitcoin core data directory.
You can add a symlink to set this up:. If required, you could dump the private keys of the cold wallet. Access to the private keys equates to full control over the Bitcoin.