What is Blockchain?

A blockchain is a distributed digital ledger that records transactions across many computers. Think of it as a shared spreadsheet that everyone can see but no one can secretly change.

Key Concepts

Decentralization: Unlike traditional databases controlled by one company, blockchains are maintained by thousands of computers worldwide. No single entity controls it.

Immutability: Once data is recorded, it's extremely difficult to change. Each block contains a cryptographic hash of the previous block, creating an unbreakable chain.

Transparency: All transactions are visible to everyone on the network. You can verify any transaction yourself.

How Blocks Work

1. Transactions are grouped together into a 'block'

2. The block is verified by network participants (miners or validators)

3. Once verified, the block is added to the chain permanently

4. The process repeats for new transactions

Why It Matters

Blockchain technology enables trustless systems - you don't need to trust a bank or company because you can verify everything yourself. This is revolutionary for finance, supply chains, voting, and more.

Real World Analogy

Imagine a classroom where everyone has the same notebook. When someone writes something, everyone copies it instantly. If someone tries to change their copy, everyone else's copies prove the change is invalid.