• Blockchain is a type of shared database that differs from a typical database in the way it stores information; blockchains store data in blocks linked together via cryptography.
  • Different types of information can be stored on a blockchain, but the most common use for transactions has been as a ledger. In Bitcoin’s case, blockchain is decentralised so that no single person or group has control—instead, all users collectively retain control.
  • Decentralised blockchains are immutable, which means that the data entered is irreversible. For Bitcoin, transactions are permanently recorded and viewable to anyone.

A blockchain is a distributed database or ledger shared among a computer network‘s nodes. They are best known for their crucial role in cryptocurrency systems for maintaining a secure and decentralised record of transactions, but they are not limited to cryptocurrency uses. Blockchains can be used to make data in any industry immutable—the term used to describe the inability to be altered.

Because there is no way to change a block, the only trust needed is at the point where a user or program enters data. This aspect reduces the need for trusted third parties, which are usually auditors or other humans that add costs and make mistakes.

Since Bitcoin’s introduction in 2009, blockchain uses have exploded via the creation of various cryptocurrencies, decentralised finance (DeFi) applications, non-fungible tokens (NFTs), and smart contracts.

Also read: How do AI and blockchain work together?

Definition of blockchain technology

At its core, blockchain is a decentralised, distributed ledger technology that enables the secure and transparent recording of transactions across a network of computers. Unlike traditional centralised systems where data is stored in a single location controlled by a central authority, blockchain distributes data across multiple nodes, ensuring that no single entity has control over the entire network.

Also read: What is the difference between fintech and blockchain?

How does blockchain work?

1. Decentralisation

Blockchain operates on a decentralised network of computers (nodes), each of which stores a copy of the entire blockchain. This decentralised structure eliminates the need for a central authority, making the system more resilient to tampering and censorship.

2. Blocks and transactions

Transactions are grouped together into blocks, which are then cryptographically linked to form a chain. Each block contains a list of transactions, a timestamp, and a reference to the previous block, creating an immutable record of all transactions that have occurred on the blockchain.

3. Consensus mechanisms

To ensure that all nodes agree on the validity of transactions added to the blockchain, consensus mechanisms are used. These mechanisms vary depending on the blockchain protocol but generally involve a process where network participants (nodes) reach a consensus on the validity of transactions through voting or computational puzzles.

4. Security

Blockchain employs cryptographic techniques to ensure the security and integrity of transactions. Each transaction is digitally signed using cryptographic keys, making it tamper-proof and traceable. Additionally, the decentralized nature of blockchain makes it resistant to attacks and single points of failure.

5. Immutability

Once a transaction is recorded on the blockchain, it cannot be altered or deleted. This immutability ensures the integrity of the transaction history and provides a transparent audit trail for all participants.