In 2012, the European Central Bank defined virtual currency as "a type of unregulated digital money, which is issued and usually controlled by developers, and is used and accepted among members of a specific virtual community." The U.S. Department of the Treasury briefly defined it in 2013 as "a medium of exchange that functions like currency in some environments, but does not have all the characteristics of real currency." The main characteristic that there is no virtual currency according to these definitions is the status as legal tender.