Digital currency or digital money is an Internet-based medium of exchange distinct from physical (such as banknotes and coins) that exhibits properties similar to physical currencies, but allows for instantaneous transactions and borderless transfer-of-ownership. Both virtual currencies and cryptocurrencies are types of digital currencies, but the converse is incorrect. Like traditional money these currencies may be used to buy physical goods and services but could also be restricted to certain communities such as for example for use inside an on-line game or social network.Digital currencies such as bitcoin are known as "decentralized digital currencies," meaning that there is no central point of control over the money supply.
A cryptocurrency (or crypto currency or crypto asset) is a medium of exchange using cryptography to secure the transactions and to control the creation of new units. Cryptocurrencies are a subset of alternative currencies, or specifically of digital currencies. Bitcoin became the first decentralized cryptocurrency in 2009. Since then, numerous cryptocurrencies have been created. These are frequently called altcoins, as a blend of bitcoin alternative.
Cryptocurrencies use decentralized control as opposed to centralized electronic money/centralized banking systems. The decentralized control is related to the use of bitcoin block chain transaction database in the role of a distributed ledger.
Bitcoin is a digital store of value and payment system invented by Satoshi Nakamoto, who published the invention in 2008 and released it as open-source software in 2009. The system is peer-to-peer; users can transact directly without needing an intermediary. Transactions are verified by network nodes and recorded in a public distributed ledger called the block chain. The ledger uses its own unit of account, also called bitcoin. The system works without a central repository or single administrator, which has led the US Treasury to categorize it as a decentralized virtual currency. Bitcoin is often called the first cryptocurrency, although prior systems existed. Bitcoin is more correctly described as the first decentralized digital currency. It is the largest of its kind in terms of total market value.