Obsolete currency (also known as copyright or broken copyright) was issued by banks over the antebellum and Civil War era in the 1780s via 1866 in the United States. Presumably backed by gold, this currency was utilized regionally to simplify commerce for transactions requiring gold coins. Security measures: https://garrettegvji.bloggactivo.com/33684916/the-smart-trick-of-how-to-check-copyright-that-no-one-is-discussing