The Basic Idea

A blockchain is a shared, tamper-resistant record of transactions maintained across many computers instead of one central authority.

Why It’s Hard to Alter

Each new block of data is cryptographically linked to the one before it, so changing old records would require rewriting every block after it — across every copy of the chain.

Beyond Cryptocurrency

While blockchain is best known for powering cryptocurrencies, the same technology is being explored for supply chain tracking, digital identity, and secure record-keeping.