A cryptocurrency (or crypto currency) is a digital asset designed to work as a medium of exchange that uses strong cryptography to secure financial transactions, control the creation of additional units, and verify the transfer of assets. Cryptocurrencies use decentralized control as opposed to centralized digital currency and central banking systems.
The decentralized control of each cryptocurrency works through distributed ledger technology, typically a blockchain, that serves as a public financial transaction database.
Bitcoin, first released as open-source software in 2009, is generally considered the first decentralized cryptocurrency. Since the release of bitcoin, over 6,000 altcoins (alternative variants of bitcoin, or other cryptocurrencies) have been created.
Coinbase is a digital currency exchange headquartered in San Francisco, California. They broker exchanges of Bitcoin, Bitcoin Cash, Ethereum, Ethereum Classic, Litecoin, Tezos, and many others, with fiat currencies in approximately 32 countries, and bitcoin transactions and storage in 190 countries worldwide. This is the number one exchange for new investors.