#TradingPairs101 Bitcoin does not have any centralized server used for its issuance, transactions, and storage, as it utilizes a public distributed network database technology called blockchain, which requires an electronic signature and is backed by a proof-of-work protocol to provide the security and legitimacy of monetary transactions. The issuance of Bitcoin is performed by users with mining capabilities and is limited to 21 million coins. Currently, the market capitalization of Bitcoin exceeds $138 billion and this is the most popular class of digital currency. The buying and selling of cryptocurrencies is available through special platforms of Bitcoin exchanges or ATMs.