A Beginner's Guide to Blockchain: Why, What, and How?

When I first started learning about blockchain and Web3, I had tons of questions—Why is this important? What even is a blockchain? How does it work? But finding beginner-friendly content that explained these things clearly was tough. So I decided to write this article for anyone who’s curious and wants to understand the fundamentals of blockchain in a simple way—before diving deep into coding, smart contracts, or crypto. 1. Why Should I Study Blockchain? Blockchain isn’t just about cryptocurrencies. It’s about trust, transparency, and decentralization. It's being adopted in industries like finance, healthcare, supply chain, real estate, and more. Here’s why learning blockchain matters: It’s a fast-growing field with huge career opportunities It encourages understanding of distributed systems It challenges the way we think about trust, ownership, and digital identity 2. What is Blockchain? The concept of blockchain was first proposed in a 1991 research paper by Stuart Haber and W. Scott Stornetta, which aimed to solve the problem of digitally timestamping documents so they couldn’t be backdated or tampered with. In simple terms: Blockchain is a distributed, immutable ledger that stores data in blocks and links them using cryptography. It's designed to be secure, transparent, and resistant to modification. 3. Applications of Blockchain Blockchain has real-world use cases beyond Bitcoin or Ethereum: Finance: Decentralized Finance (DeFi), cross-border payments Healthcare: Secure medical records Supply Chain: Transparent product tracking Voting Systems: Tamper-proof digital voting Digital Identity: Verifiable credentials without central authority 4. Hashing Algorithm Hashing is the backbone of blockchain security. A hash is a unique fixed-size string output for any input data. Even a tiny change in input gives a completely different hash. It's used to connect blocks together securely. 5. Immutable Ledger Once data is recorded on the blockchain, it cannot be changed. If a hacker tries to change data in a block: The hash of that block changes This breaks the link with the next block The entire chain after that becomes invalid This property makes blockchain tamper-proof. 6. Centralized Network vs Distributed P2P Network In traditional systems: A central authority controls everything (single point of failure) In blockchain: It’s a peer-to-peer (P2P) network where every node has a copy of the ledger There’s no single point of control, and data recovery is easier in case of an attack 7. Distributed Peer-to-Peer Network The more nodes (computers) in the blockchain, the harder it is to attack. If one node is hacked, the rest reject its data The network validates and maintains consistency This makes blockchain highly secure and resilient 8. Blockchain Mining Mining is the process of: Validating transactions Solving complex mathematical problems Adding new blocks to the blockchain Miners are rewarded for their work, which keeps the network running. 9. Byzantine Generals Problem This is a famous problem in distributed computing: How can multiple parties agree on a decision, even if some of them are unreliable? Blockchain solves this using Byzantine Fault Tolerance (BFT), which ensures: The majority honest nodes reach consensus The system can tolerate some faulty/malicious nodes 10. Consensus Protocol

Apr 18, 2025 - 11:06

A Beginner's Guide to Blockchain: Why, What, and How?

When I first started learning about blockchain and Web3, I had tons of questions—Why is this important? What even is a blockchain? How does it work? But finding beginner-friendly content that explained these things clearly was tough.
So I decided to write this article for anyone who’s curious and wants to understand the fundamentals of blockchain in a simple way—before diving deep into coding, smart contracts, or crypto.

1. Why Should I Study Blockchain?

Blockchain isn’t just about cryptocurrencies. It’s about trust, transparency, and decentralization. It's being adopted in industries like finance, healthcare, supply chain, real estate, and more.

Here’s why learning blockchain matters:

It’s a fast-growing field with huge career opportunities
It encourages understanding of distributed systems
It challenges the way we think about trust, ownership, and digital identity

2. What is Blockchain?

The concept of blockchain was first proposed in a 1991 research paper by Stuart Haber and W. Scott Stornetta, which aimed to solve the problem of digitally timestamping documents so they couldn’t be backdated or tampered with.

In simple terms:

Blockchain is a distributed, immutable ledger that stores data in blocks and links them using cryptography. It's designed to be secure, transparent, and resistant to modification.

3. Applications of Blockchain

Blockchain has real-world use cases beyond Bitcoin or Ethereum:

Finance: Decentralized Finance (DeFi), cross-border payments
Healthcare: Secure medical records
Supply Chain: Transparent product tracking
Voting Systems: Tamper-proof digital voting
Digital Identity: Verifiable credentials without central authority

4. Hashing Algorithm

Hashing is the backbone of blockchain security.

A hash is a unique fixed-size string output for any input data.
Even a tiny change in input gives a completely different hash.
It's used to connect blocks together securely.

5. Immutable Ledger

Once data is recorded on the blockchain, it cannot be changed.

If a hacker tries to change data in a block:

The hash of that block changes
This breaks the link with the next block
The entire chain after that becomes invalid

This property makes blockchain tamper-proof.

6. Centralized Network vs Distributed P2P Network

In traditional systems:

A central authority controls everything (single point of failure)

In blockchain:

It’s a peer-to-peer (P2P) network where every node has a copy of the ledger
There’s no single point of control, and data recovery is easier in case of an attack