Bitcoin
BASICSDEFINITION
A digital money and payment network with no company, government, or bank in charge — secured by cryptography and a fixed supply of 21 million coins.
Launched in January 2009 by the pseudonymous Satoshi Nakamoto, Bitcoin solved a problem thought unsolvable: transferring value online without a trusted middleman. Every transaction is recorded on a public ledger (the blockchain) maintained by thousands of independent computers.
Capital-B Bitcoin usually means the network and protocol; lowercase bitcoin (or BTC) means the currency unit. Its fixed 21-million supply is the property everything else — the halving, the mining industry, the "digital gold" thesis — flows from.
IN A SENTENCE
“She keeps five percent of her savings in bitcoin as a hedge against currency debasement.”
Key facts
Common questions
Who controls Bitcoin?
Nobody and everybody: changes require broad agreement among users, miners, and developers. No party can unilaterally alter the rules.
Is bitcoin legal?
Legal to own and use in most countries, with varying tax and reporting rules. A few jurisdictions restrict it — check yours.