What is BlockChain | Developer Blog | Punyakrit Singh Makhni

What Is A Blockchain

Ever wondered why banks and governments have so much control over things like money, transactions, and records?

Traditionally, these systems are centralized. A single authority owns the database, verifies transactions, and decides what is valid. This means users have to trust one middleman to be honest, secure, and always available.

Blockchain was created to solve this problem.

At its core, a blockchain is a shared digital ledger that is not owned by any single entity. Instead of one central authority, the ledger is maintained by many independent computers called nodes.

Each node verifies transactions by following predefined rules and performing cryptographic calculations. When most nodes agree that a transaction is valid, it gets added to the ledger. This agreement process is called consensus.

Because the ledger is shared, verified by many participants, and updated only when there is agreement, no single party has control. This removes the need for trust in a central authority and makes the system transparent, secure, and decentralized.

In simple terms:

Blockchain replaces trust in institutions with trust in code and consensus.

History of Blockchain

The origin of blockchain comes from Bitcoin. Bitcoin is a digital currency that exists on a blockchain, also known as the Bitcoin blockchain.

Bitcoin is often called digital gold because it has a finite supply, just like gold. People value Bitcoin because no government or bank can act as a middleman or control it. The network is decentralized and runs without any central authority.

Another important reason people value Bitcoin is that no government or single institution can act as a middleman. No one can print more Bitcoin, freeze accounts, or control the network. The rules are enforced by code and consensus, not by authority.

Bitcoin proved that decentralized systems could work at a global scale, and it laid the foundation for everything blockchain-enabled today.

A few years later, Ethereum came into the picture with a new idea. Instead of using blockchain only to trade money, Ethereum asked: why not use it for agreements where the rules are unbreakable and everyone must follow them?

Ethereum made this possible by allowing code to run on the blockchain. These programs are called smart contracts. Instead of just tracking money, Ethereum can run code and create agreements that execute automatically when conditions are met.

Smart Contracts

Smart contracts are programs that run on a blockchain. They are written as code and automatically execute when predefined conditions are met.

Once deployed, a smart contract cannot be changed or broken. No middleman is needed because the rules are enforced by code, not by people. This makes agreements transparent, trustless, and secure.

Platforms like Ethereum allow developers to create smart contracts for things like payments, lending, NFTs, and decentralized applications. Instead of trusting a third party, users trust the contract logic itself.

Benefits of Blockchain

In the real world, governments keep track of almost everything. For even simple actions, you often need permission from authorities or powerful intermediaries.

With blockchain, you are your own owner. You don’t need permission from anyone. It works the same way for everyone, unlike traditional centralized systems where control lies with a few entities.

Blockchain doesn’t care who you are. The protocol has no favorites. It simply follows mathematics and predefined rules.

It is decentralized. Governments and banks can be shut down, but a blockchain runs on thousands of computers around the world. To stop it completely, you would have to shut down the internet itself.

Blockchain is transparent. Traditional systems are opaque and can be changed by governments or regulators at any time. On a blockchain, all data is visible, rules are written in code, and once added, they cannot be changed.