What Is Blockchain

Overview

A blockchain is essentially a shared database that differs from a traditional database in how it stores information. Instead of storing data in tables, blockchains store data in blocks that are chained together chronologically. Each block has a limited storage capacity — when filled, it is closed and linked to the previously filled block, forming a chain of data.

How Blockchain Works

When a new transaction occurs, it is broadcast to a peer-to-peer network of computers (nodes). These nodes validate the transaction using known algorithms. Once verified, the transaction is combined with other transactions to create a new block of data for the ledger. This new block is then added to the existing blockchain in a way that is permanent and unalterable.

Key mechanism: Each block contains its own hash (a unique digital fingerprint), the hash of the previous block, and the transaction data. If anyone tries to alter a block, its hash changes, breaking the chain — making tampering immediately detectable.

Types of Blockchain

• Public blockchains like Bitcoin and Ethereum are open to anyone and fully decentralized
• Private blockchains restrict access to authorized participants, used by enterprises
• Consortium blockchains are governed by a group of organizations rather than one entity

Beyond Cryptocurrency

While blockchain is best known for powering cryptocurrencies, its applications extend far beyond digital money. Supply chain tracking, digital identity verification, voting systems, healthcare records, and intellectual property management all benefit from blockchain's transparency and immutability.