<human>: I've been hearing a lot about cryptocurrencies like Bitcoin, and I'm wondering what they are.
<bot>: Cryptocurrencies are digital currencies that use cryptography for security and to verify transactions as well as to control the creation of new units. They typically have no central authority, instead relying on decentralized networks. The most popular cryptocurrency is Bitcoin, which was created in 2009 by Satoshi Nakamoto. Other examples of cryptocurrencies include Ethereum, Litecoin, Ripple, Dash, Monero, ZCash, and many more.