🔗 How Blockchain Works: The Tech That Powers Trust

#web3 #blockchain #cryptocurrency #beginners

You’ve probably heard that blockchain is “immutable” and “decentralized” — but what does that actually mean? Let’s break down how blockchain works under the hood — without turning it into a crypto-induced coma.

🧱 Blocks, Chains & Hashes

At its core, a blockchain is a chain of blocks — pretty straightforward, right?
Each block contains:

A list of transactions
A timestamp
A cryptographic hash of the previous block

This hash acts like a digital fingerprint — unique and tamper-proof. If someone tries to change the contents of a block, its hash changes, breaking the entire chain. That’s like trying to remove a Jenga piece from the middle of the tower — the whole thing collapses.

🔐 What Is a Cryptographic Hash?

A cryptographic hash function takes input data and returns a fixed-size string of characters (like SHA-256 in Bitcoin). This output — the “hash” — is:
✅ Unique (same input = same output)
✅ Irreversible (you can’t reverse-engineer the input from the hash)
✅ Tamper-evident (even changing one comma in the input completely changes the hash)

This is how blockchain secures its data — by creating a “chain of trust” using hashes.

🧠 Consensus: How Everyone Agrees

In a decentralized system, who decides what’s true?
That’s where consensus mechanisms come in.

Two popular ones are:

Proof of Work (PoW): Miners compete to solve complex math puzzles. First to solve it adds the next block and gets rewarded. (Used in Bitcoin)
Proof of Stake (PoS): Validators are chosen based on the amount of crypto they’ve staked. Less energy-intensive, and gaining popularity. These systems ensure that everyone in the network agrees on the current state of the blockchain — preventing fraud, double-spending, and chaos.