A cryptocurrency is a digital or virtual currency that often uses a blockchain for security. A blockchain is a large system of computers working together to keep something safe, it cannot be hacked, and is usually used to verify payments or to make an exchange, A cryptocurrency is difficult to counterfeit because of this security feature. The first cryptocurrency come alive was Bitcoin, which was launched in 2009 by an individual or group known under the alias, Satoshi Nakamoto. As of September 2015, there were over 14.6 million bitcoins in circulation with a total market value of $3.4 billion. Bitcoin’s success has spawned a number of competing cryptocurrencies, such as Litecoin, Namecoin, and PPCoin. Cryptocurrencies make it easier to transfer funds between two parties in a transaction; these transfers are facilitated through the use of public and private keys for security purposes.