What Is a Blockchain?

A blockchain is best thought of as a distributed computer, where multiple nodes work together to store and update data in a trustless, append-only manner—offering digital ownership, public verifiability, and censorship resistance without central authority.

Three Core Pillars:

1. Cryptography

   • Public/Private Keys: Prove ownership of digital assets or identities.

   • Hashing: Creates unique “fingerprints” for data and transactions, ensuring integrity and immutability.

2. Distributed Ledger

   • A shared database replicated on many computers around the world.

   • Organized as blocks in an “append-only” chain, where each block references the hash of the previous block.

3. Consensus Protocol

   • Ensures that all nodes agree on which blocks (and transactions) are added to the chain.

   • Involves selecting a leader (a validator) to propose blocks and voting mechanisms.

This combination enables trust-minimized systems for payments, DeFi, asset ownership, and data management—capabilities difficult to replicate with traditional databases.