Bitcoin is a digital currency, a decentralized system that records transactions in a distributed ledger called a blockchain.
Bitcoin miners run complex computer equipment to solve complex puzzles to confirm groups of transactions called blocks; after success, these blocks will be added to the blockchain record, and the miners will be rewarded with a small amount of Bitcoin.
Other participants in the Bitcoin market can buy and sell tokens through cryptocurrency exchanges or peer-to-peer.
The Bitcoin ledger is protected from fraud through an untrusted system; Bitcoin exchanges are also committed to preventing potential theft, but high-profile thefts occur from time to time.