According to the G4S "Global Cash Report 2018", cash settlement is direct and final, especially for small value transactions with a ratio of 60-80%. In short, it is a fundamental pillar of civilization, because cash is the main mechanism for the world to pay and trade. If cash suddenly disappears, the economies of each country will be seriously affected. In the process of connecting the cash market to the digital economy, cryptocurrency plays an important role. In particular, stable coins that are often anchored with French currency. Although most stable currencies are pegged to the US dollar, their scope is expanding. As a form of digital cash, the stable currency can be integrated with any digital service offered by the company in the market.