Bitcoin

Bitcoin is a digital currency that operates without a central authority, relying instead on a public, distributed ledger called a blockchain. Introduced by the pseudonymous developer Satoshi Nakamoto in late 2008, the network began processing transactions in January 2009.

Unlike government-issued money, Bitcoin’s total supply is permanently limited to 21 million coins. Approximately every four years, the amount of new bitcoins created with each block is halved, gradually reducing the rate of new supply until it reaches zero. This predictable, capped issuance stands in contrast to traditional money, which can be printed in unlimited amounts.

The Bitcoin network uses a Proof-of-Work system for security and transaction validation. All participants maintain and verify the same blockchain, which records every confirmed transaction. Once a block is added to this ledger, its data cannot be changed or deleted—new information is only ever appended.

In writing, “Bitcoin” (capital B) often refers to the system, network, or protocol as a whole, while “bitcoin” (lowercase b) denotes the actual currency—the units sent and received between users or traded on exchanges.