Spending BTC

Spending your Bitcoins is a secured process that requires several steps.
It involves moving files between your online PC and your offline wallet machine.
USB flash disk is probably the most convenient medium to use for this purpose.

Never move any files others than the ones that you actually need to move, which are:
  • balance/ folder created by balio or balance.zip / payment.zip file generated by WebUI - you move it from online PC to wallet machine.
  • Text files with signed transactions - these you move from wallet machine to online PC.

Assuming that you would not sign a wrong transaction, nothing in the files you move between the two points is security sensitive, so you do not need to worry about protecting the medium (USB disk).

1. Export your balance

In order to spend your coins you will need to provide a current balance data to the computer that runs your wallet.

If you have no client: use balio tool If you have a running client: use WebUI
There is a tool balio that can fetch a balance of your wallet from a public block explorers.

Run the tool from a command line with the file name of your wallet as the command line parameter (e.g. balio wallet.txt).
Eventually enter the list of space separated BTC addresses that you want to fetch the balance for (balio 1Hz96kJKF2HLPGY15JWLB5m9qGNxvt8tHJ 3NEDeMiXubepj68RGCTXJyJc83cYXMpusw).

This should create the balance/ folder in the current directory, ready to be moved your wallet machine.

Note: fetching the balance this way exposes your privacy.
To use balio through Tor, set TOR environment variable in your system, pointing it to your tor's socks proxy (e.g. TOR=localhost:9050).
Additionally, despite of using Tor, to further protect your privacy try to fetch balance of single addresses instead of entire wallets.
From the moment a content of wallet.txt file is properly stored in your browser, you can check and export your balance. Do it on the Wallet tab.

To spend your coins, you can choose one of the two ways here. It is recommended to use MakeTx page that allows you to assemble a transaction using a convenient, interactive way.

MakeTx tab: Use Coin Control Wallet tab: download balance.zip

After you fill in all the transaction details, it will give you payment.zip with the exact command that you shall execute at the wallet machine.

Use Wallet page of WebUI to download balance.zip file.

Extract the zip file to get the balance folder.

2. Sign your transaction

As mentioned before, to spend your money you need to move the most recent balance/ folder, from online PC to wallet machine.
For security reasons, you should execute wallet command only on offline machine - one that never was nor will be connected to Internet.

Manual mode

To spend your coins, order the wallet to make and sign a new transaction, using a command like:
    wallet -send 1JbdKe4eBwtexisGTbCKY5v5CfphtdZXJs=0.01
Please note no spaces between the address, the equal sign and the value.
The value represents the amount in BTC, which you request to send to the given address.

There are also other switches which you may find useful at this stage.
One of them (-fee) allows you to control the transaction's' fee.
To see all the wallet's options, just run wallet -h

Smart mode

If you used MakeTx tab to make the transaction, all you have to do now is to extract payment.zip file at the wallet computer and execute there the exact command from the pay_cmd file. For further convenience, you can rename it to pay_cmd.sh or pay_cmd.bat by editing the config file.

3. Verify signed transaction

If everything goes well with the wallet's' -send ... command, it will create a text file with a signed transaction. The file is named like 01234567.txt - this is the file you need to move to your online node in order to notify the network about your payment. Before you broadcast your signed transaction to the network, verify carefully that it does exactly what you intended.

Wallet WebUI (requires client)
To see a decoded content of a transaction, execute:
wallet -d rawtxdata.txt
Use PushTx button or Upload Transaction File form.
After you upload the transaction, you should see it decoded.
Then have a look if it makes sense. And if it does, send it away...

Note: always verify transaction before broadcasting it!
Verify that the decoded content of a transaction matches exactly what you intended to spend.
If what you see would not be what you wanted, do not broadcast the transaction, but destroy the transaction file instead.
If you follow this simple rule, your money will be safe, even in case if there was a critical bug in the wallet application that would otherwise destroy your coins (which we hope there isn't).

4. Broadcast the transaction

After making sure that the transaction does indeed what you intended, you must broadcast it to the network, in order to actually move your coins.

WebUI (requires client) TextUI (requires client) Web services
Load the transaction using the client's WebUI. Click on the envelope icon with a green arrow to broadcast a loaded transaction to the network. Coming back to Transactions tab later, press the button in the "Own TXs" row, to see all the transactions you've loaded (those with a red background are yours). You can also unload a previously loaded transaction by clicking on the red X icon. Use stx command with the transaction ID as its parameter (you had the ID printed, when loading it). Use any web page that allows you to push a raw transaction to the bitcoin network.

For instance:
• https://blockchain.info/pushtx
• https://coinb.in/send-raw-transaction.html
• More at https://en.bitcoin.it/wiki/Transaction_broadcasting

Just copy the text from the transaction file, paste it into the form and push the button.

Note: being concerned about exposing your IP, you may want to access the web page via Tor.

Re-broadcasting transactions
The client never broadcasts transactions unrequested, so if your transaction does not appear in the chain soon enough, you may want to re-broadcast it, using the same method as for the initial broadcasting. There may of course be other reasons why your transaction does not get confirmed (usually because the fee was to low), in which case re-broadcasting it will not help you much.

There is also a TextUI command stxa that re-broadcasts all the transaction that have been loaded, but not yet confirmed by the network. Note that when a transaction gets mined into a block it gets removed from the list automatically.