Bitcoin

The Bitcoin logo

Bitcoin (ticker BTC) is the first decentralized cryptocurrency, a digital currency that can be sent directly between users without a bank or other intermediary. It was introduced by the pseudonymous Satoshi Nakamoto in the 2008 white paper "Bitcoin: A Peer-to-Peer Electronic Cash System", and the network launched in January 2009.

Design

The white paper proposed a solution to the "double-spending problem", the risk that a digital token could be spent twice, without relying on a trusted third party. Transactions are grouped into blocks and timestamped "into an ongoing chain of hash-based proof-of-work", forming a record that cannot be changed without redoing that work. The longest chain is accepted as the valid history, so the system remains secure as long as most computing power is controlled by honest participants.

Participants known as miners compete to produce each new block by solving a computational puzzle, and are rewarded with newly created bitcoin. Blocks are added about every ten minutes, and the rate of issuance falls over time until it halts at a fixed total supply of 21 million bitcoin. The block reward halves every 210,000 blocks, roughly every four years.

History

Nakamoto mined the first block, known as the genesis block, on January 3, 2009, embedding in it a newspaper headline about British bank bailouts. Nakamoto stopped participating in the project around 2010, and their identity remains unknown. Bitcoin's limited scripting ability led Vitalik Buterin, who co-founded Bitcoin Magazine in 2011, to propose Ethereum as a more programmable blockchain in 2013.

Bitcoin remains the largest cryptocurrency by market value. In his 2026 essay "The Cryptographic World Computer", Buterin used the original Bitcoin design as the baseline against which he measured how far Ethereum had since evolved.

See also

• Ethereum
• The Cryptographic World Computer
• Zero-Knowledge Proof
• Nick Land