What is cryptocurrency?

A cryptocurrency is a form of digital money. While the specifics tend to vary by currency, one common aspect of cryptocurrencies is that they are designed to be decentralized and difficult to modify without widespread agreement. With a decentralized system, it is nearly impossible to hack or alter the information outside of the built-in methods—anything that is different is rejected by all the other machines hosting the data. Many cryptocurrencies are built using blockchains, which are permanent records of transactions added to a single ongoing ledger. Cryptocurrencies often have unique traits designed to separate them from other currencies, such as speed of operation or anonymity for users.