Bitcoin is a decentralized digital currency, without a central bank or single administrator, that can be sent from user to user on the peer-to-peer bitcoin network without the need for intermediaries. Transactions are verified by network nodes through cryptography and recorded in a public distributed ledger called a blockchain.
Bitcoin was invented in 2008 by an unknown person or group of people using the name Satoshi Nakamoto, and started in 2009 when its source code was released as open-source software.
Bitcoins are created as a reward for a process known as mining. They can be exchanged for other currencies, products, and services. As of February 2015, over 100,000 merchants and vendors accepted bitcoin as payment. Bitcoin can be bought on online exchanges and some brick-and-mortar businesses.
A 2015 survey showed bitcoin users tend to be overwhelmingly white and male, but of varying incomes. The people with the most bitcoins are more likely to be using it for illegal purposes, the survey suggested.
Bitcoin is pseudonymous, meaning that funds are not tied to real-world entities but rather bitcoin addresses. Owners of bitcoin addresses are not explicitly identified, but all transactions on the blockchain are public.
In addition, transactions can be linked to individuals and companies through “idioms of use” (e.g., transactions that spend coins from multiple inputs indicate that the inputs may have a common owner) and corroborating public transaction data with known information on owners of certain addresses.