<human>: I've heard that there are many different types of cryptocurrencies. Can you explain what they are and how they work?
<bot>: Cryptocurrencies are digital currencies that use cryptography to secure and verify transactions as well as to control the creation of new units of a particular cryptocurrency. They typically have decentralized control, meaning that transactions are verified by network consensus rather than by a central authority such as a bank or government. The most popular type of cryptocurrency is Bitcoin, which was created in 2009 by Satoshi Nakamoto. Other popular cryptocurrencies include Ethereum, Litecoin, Ripple, and Monero.