Bitcoin Core

Using bitcoin core 0.9.2.1.  Bitcoin core has a “testnet” mode.  Test net allows you to try the software with test bitcoins, which are free.

Pre reqs

The first we start Bitcoin Core, it will connect to peers and begin downloading the entire block chain.  This will take days, if not weeks.  And will require over 25GB of disk.  You should check that you have enough disk space first.   Further more, the block chain grows at over 5mb a day.  So I would recommend you have at least another 15GB free.  If you are not willing to wait over a week to get started, I also recommend you choose a light weight wallet.

OSX:

1. Click the Apple logo
2. About This Mac
3. Click “More Info…”
4. Click the storage tab
5. You will then see ?GB of ?GB free.  Confirm you have enough disk space.  If you do not, then choosing a lightweight wallet might be a better option.

Windows 7 & 8:

We also recommend that your hard drives are encrypted.

OSX:

Windows 7 & 8

Download Bitcoin Core

You can download the installer from https://bitcoin.org/en/download

Tip:  Once you have downloaded the installer, you should check the signature is the same as what is listed on bitcoin.org.

Install Bitcoin Core

OSX:

Windows:

Receiving bitcoin

To begin our lab, we must first receive some bitcoin or test net coins.   When we installed Bitcoin Core we are give an address.  We can use this to receive bitcoin.  To view the address, we select;

1. File
2. Receiving addresses
3. Select the address and click copy.  This will copy the address to your clipboard.

You can now email this address to whom every you like so they can pay you.   The transaction will only show in your wallet, once the block chain is fully downloaded.

Aside:  Generally, we should create a new address each time we want to receive coins.  This does a number of things;

1. Protects your security
2. Provides security to the network.

Because we create a new address, it has never been seen on the block chain.  Unlike an email address, bitcoin addresses are created “offline”.   Lets have a look at this now;

1. Select the address
2. Paste it into your browser after the the url https://www.blockchain.info/address/<new address>
   1. Eg https://www.blockchain.info/address/19vQxvsj9RhP6dZzDJPr137iciyyUCNMhW
3. We see on the right hand column 0 transactions.

Note:  Blockchain.info is a free third party site, which allows bitcoin users to perform queries on the block chain from a web browser.   This is a great tool that we will make use of during the course.

To create a new address, simple click the new button.  You will now see a dialog box where you can add a label too.  A label is for your reference only.   This could be something like “Payment for Friday Beers”.   Click ok and you will now see this in your list of receiving addresses.

Note:  Labels are not unique.

Sending bitcoin

Sending bit con from Bitcoin core is pretty straight forward.  The client includes a mandatory miners fee which at is 0.0001 BTC

13v1opxapWyhDFXCeYjgnnGP7TUxgk28La

Backing up

You private keys are stored in the file wallet.dat.  Each time you create a receiving address, you will need to backup your wallet.  You should not only backup often, but you should also test your backups frequently.   Backups can be stored to a number of different media too.

CDs or DVS

USB drives

Paper or physical media

Import a backup

You can import a single private key via the debug window.   To get to the console window;

1. Help
2. Debug window

In the command line type importprivkey follow by the private key (in wallet import format) and a label if you like.  A label can be anything remember.  Its just something to help you identify the address.

We can make a private key to import via brainwallet.org.  Select the generator tab.  In the passphrase box, type correct horse battery staple.  You will see the private key 5KJvsngHeMpm884wtkJNzQGaCErckhHJBGFsvd3VyK5qMZXj3hS generated.

Eg importprivkey 5KJvsngHeMpm884wtkJNzQGaCErckhHJBGFsvd3VyK5qMZXj3hS “correct horse battery staple”

Other