Bitcoin is a decentralized digital currency, introduced in a 2008 whitepaper by an unknown person or group using the pseudonym Satoshi Nakamoto. It was released as open-source software in 2009.

Key Features:

1. Decentralization: Bitcoin operates without a central authority. Transactions are conducted directly between users through a peer-to-peer network.

2. Blockchain Technology: Bitcoin uses a blockchain, a transparent and immutable ledger where all transactions are recorded.