The cryptocurrency bitcoin — money backed by mathematics rather than governments or precious metals — first came into existence around 2009. The digital currency, which is “mined” by computers, has since gained a solid number of adherents, and nearly as many questions.
https://www.forbes.com/sites/forbestechcouncil/2017/03/31/five-thoughts-on-what-bitcoins-rise-in-value-means/#894f45732bd9