Bitcoin (BTC) is a decentralized cryptocurrency that was originally described in a 2008 whitepaper by a person or group of people using the alias Satoshi Nakamoto. It was launched soon after, in January 2009. Bitcoin is a peer-to-peer online currency, meaning that all transactions happen directly between equal, independent network participants, without the need for any intermediary to permit or facilitate them. Bitcoin was created to allow online payments to be sent directly from one party to another without going through a financial institution.

The security of the Bitcoin network relies on this decentralization since the Bitcoin network makes decisions based on consensus. If there is disagreement about whether a block should be included in the block chain, the decision is effectively made by a simple majority consensus, that is, if greater than half of the mining power agrees. While centralized systems are more efficient, they also present a larger target for attackers who wish to compromise the system. In contrast, the decentralized nature of the Bitcoin network makes it much more resilient to attack. This is one of the key features that makes Bitcoin an attractive option for many people.