What is Cryptocurrency?
Cryptocurrency is a decentralized digital currency that relies on encryption and participation to record transactions on a public ledger.  
While Bitcoin is the most well-known cryptocurrency, several additional currencies have become relevant, and have vastly expanded the need for digital currency mining.
 Similiar to the trade of currencies between countries, Cryprocurrencies trade for other decentralized cryprocurrencies on an open market.
Cryprtocurrency exchanges allow decentralized currencies to trade with traditional currencies and even Paypal.