I’m sure over the last year you have heard about bitcoin and blockchain technology, either through advertisement or some friend/family member who has gone all in with an investment. The problem is that alot of people invested in it or not does not understand the fundamentals behind blockchain technology, in which we are about to elaborate on.

What is a blockchain?

A Blockchain is a kind of database: while a normal database is located on a server, a blockchain is distributed among different users.
For example, the Facebook’s database is located on a protected server and no one can access the information. The Bitcoin’s blockchain instead is located on servers and computers (called nodes) of all the Bitcoin users.

All the transactions that occur between e-wallets are stored on the bitcoin’s blockchain. All the servers and the computers that are using bitcoin have the same copy of the blockchain stored on their hard disk.

There are many kinds of blockchain with different features, like EthereumRipple and Qtum. Some of them are more suitable to handle currency, others are used to transfer the ownership of assets (eg supply chain).

You don’t need to download all the blockchain to your computer in order to use Bitcoin (or any other blockchain technology) as the current size of Bitcoin’s blockchain is over 160 GB and it can easily drain the resources of your computer. To avoid this issue there are different types of e-wallets.

What is the difference between Bitcoin and Blockchain?

Blockchain is the technology behind bitcoin: bitcoin cannot exist without a blockchain. It is like the Internet and Facebook: Facebook cannot exist without the Internet.

If the bitcoin’s blockchain is on my computer, can I add loads of bitcoins in my e-wallet?

The blockchain is famous for its security: once the data is there it is impossible to modify it.

The blockchain consists of a chain of blocks, where every block contains data (for instance money transactions, documents or personal data).
When a new block is to be added to the chain, it has to be verified by the network of nodes first, and once this is done, the transaction can be inserted in the blockchain. There are mining and a consensus protocol standing behind this phase.
The blocks are connected with each other in a way that if I edit the content of one block I must edit all the following blocks, moreover to edit a block you need the consensus of other nodes.
Hence the more people are using a blockchain, the more secure the system is.

At present there are over 9000 nodes in the Bitcoin network.

Are you telling me that the blockchain has no flaws?

Technically it is possible to break into the blockchain but you will need more than half of the computational power of the whole network (so basically it is impossible).

Experts are worried that blockchain cannot resists a quantum attack. A quantum computer is a next generation computer with a huge computational power. It can come out in 10 or 20 years but by that time also the blockchain technology will evolve. For instance Iota is a new kind of blockchain with a different structure and it can resists a quantum attack.

Why don’t we continue using a normal database as we did so far?

The blockchain is shaking many industries but it cannot be used everywhere. For example there is no sense in using blockchain to store the data of this website. But it makes a big difference when the third party is involved.
If you have to transfer money, the bank is the third party that takes the money from you and transfers it to the recipient.

In the Bitcoin system there is no one between you and the recipient, the transfer is direct and it takes around 10 minutes.

The blockchain technology is applied in many industries such as music, real estate, energy and now printing.