Bitcoin is 比特幣an online currency, or digital asset, which uses cryptography for security and operates independently of central banks. It was created in 2009 by an unknown person or group of people using the pseudonym Satoshi Nakamoto.　　The name "Bitcoin" comes from the first letter of each word in the English alphabet, starting with "B". Bitcoin transactions are recorded on a public ledger called the blockchain, which is decentralized and maintained by many individuals around the world.　　Bitcoin has gained popularity among investors and enthusiasts due to its potential for high returns, but it also has faced criticism for its lack of regulation and the potential for fraud and theft.　　As of 2021, there are over 33 million active users worldwide and the value of Bitcoin has fluctuated significantly over the past decade. The price of Bitcoin can range anywhere from a few dollars to tens of thousands of dollars per coin.