A cryptocurrency is a digital or virtual currency that is secured by cryptography, which makes it nearly impossible to counterfeit or double-spend. Many cryptocurrencies are decentralized networks based on blockchain technology—a distributed ledger enforced by a disparate network of computers. And the first cryptocurrency ever created is Bitcoin.
Cryptocurrency is not issued by government or central authorities. That make them cannot control it.
How is it work
Cryptocurrencies can be used to buy goods and services. But some other currencies, use cryptography to provide secure online transactions.
While cryptocurrencies can be used to buy things, much of the interest in these unregulated currencies is to trade them for profit. Buy them now and trade it later when they become more valuable.