What is a blockchain?
A blockchain is a shared record of transactions that lots of computers hold copies of at the same time. Think of it as a public spreadsheet that no single person owns — and that's very hard to cheat.
Why "block" and "chain"?
Transactions are bundled into blocks. Each new block is mathematically linked to the one before it, forming a chain. Because every block references the last, you can't quietly edit an old entry without breaking every block after it — which the rest of the network would instantly reject.
Who keeps it honest?
Thousands of independent computers ("nodes") each store the ledger and must agree before a new block is added. This agreement process (called consensus) is what removes the need for a bank or company to be the trusted middleman.
Why it matters for you
The blockchain is why crypto can be sent worldwide, 24/7, without a bank — and why balances are public and verifiable. It doesn't make any coin a good or safe investment; it's just the plumbing underneath.
Frequently asked
What is a blockchain in simple terms?
A blockchain is a shared digital ledger of transactions copied across many computers, so no single party can secretly change it. New records are added in linked 'blocks'.
Why is a blockchain considered secure?
Because records are chained together and verified by a distributed network, altering one old entry would mean overpowering the entire network at once. That makes tampering extremely hard.
Is blockchain only used for crypto?
No, the underlying idea is used in other areas too, but cryptocurrencies are its best-known and most widespread application so far.
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