What are Cryptocurrencies ?

 A cryptocurrency, crypto-currency, crypto, or coin is a digital currency designed to work as a medium of exchange through a computer network that is not reliant on any central authority, such as a government or bank, to uphold or maintain it.

transactions are verified and records maintained by a decentralized system using cryptography, rather than by a centralized authority. Basically, they are the currency made by people with the help of people. The transaction is done with the help of some people who are known as the Miners and a chunk of the amount are left with them .