I’m sure you’ve heard of a blockchain before, especially if you’ve heard anything about crypto currency, and more recently Web3. But what exactly is a blockchain?
A blockchain is a database that is different from a conventional database as it is distributed between many different nodes (computers) rather than being stored on a single server, or a collection of databases owned by a single company. It is decentralised. All the data stored is contained within data structures called blocks, which are linked together, hence the name blockchain. This collection of nodes spread out creates a secure database that is much less vulnerable to security issues or accidents, however, the most significant feature is that anyone can take part in the blockchain.
Well, now you know what a blockchain is, but how exactly does it work? As previously stated, the blockchain is comprised of data stored in data structures called blocks, each one having a certain storage capacity. As new data enters the blockchain, it is added to a fresh block – or one that has space. Once the block has reached its maximum storage capacity, it is closed and then chained on to the previously filled block. This process of creating, filling and linking blocks is what makes a long chain of data linked in chronological order, that is an immutable and irreversible data structure.
What makes the idea of blockchains so attractive and more preferable to conventional databases in recent times, are 3 main things: Decentralisation, Transparency and Security
In terms of decentralisation, it refers to how data can be spread over many different nodes compared to traditional databases which are usually based in one central location and are owned by a single company or organisation. If the database is spread out on the blockchain, then there will be no single point of failure or control, meaning it will be much more difficult for a service to fail. Also, if something were to happen to a block, the other blocks would be able to cross reference and accurately locate the incorrect block.
The transparency of the blockchain is admirable, as all transactions can be viewed and everyone can see what is going on at all times on the blockchain. This can be achieved by having a node yourself or by using a blockchain explorer. All records are encrypted – however – they can all be decrypted using your personal public key. All users have the ability to decrypt records, but doing so will reveal that the record has been decrypted and viewed by you, as your public decryption key is unique to you. Security is a profound feature of blockchain databases. If a hacker wanted to control, alter or cause significant harm to the blockchain, they would have to have control of over 50% of the nodes on the blockchain and reprogram each copy of the blockchain that each node had. This would require an incredibly significant amount of resources to achieve, such a vast amount that it would most likely render the entire ordeal pointless. If the hacker wasn’t able to take control of more than half of the nodes, then because of how the blockchain is set up, all the other nodes would detect the incorrect copy of the chain and just simply expel that chain and continue with its usual operations.
Throughout this article, I have been singing the praises of blockchains, but it doesn’t come without its downsides. Things such as: its slower process times, the cost of the technology necessary, the difficulty in scaling the network and the inefficiency of some of its processes.
At the moment, the main use of blockchains is to record transactions for crypto currencies, as an immutable and secure ledger. Although, there are many more possible uses for this technology and is a field that has a great amount of room to grow. Despite its drawbacks and its current immaturity, blockchain technology is something to look forward to.