Abstract: Digital currencies have received remarkable development in recent years. As a new product of the digital economy era, digital currency innovates rapidly, and constantly impacts the existing framework of society, economy, finance and technology. Therefore, understanding the influences of digital currency is of great significance. In June 2019, Facebook publicized Libra, which is a supranational cryptocurrency issued by large-scale institution. Libra, backed by Facebook with a large global user base, has attracted close attention from governments and central banks globally. This paper employs Libra as an important case to explore the impact of supranational digital currency of large-scale institution, and to investigate how to better design and develop digital currency. Libra meets the demand of business model innovation of Facebook, and it is a strategic step of Facebook to diversify business, enter developing market and form business ecosystem. This paper argues that digital currencies like Libra impose huge challenges to the existing legal and regulatory framework, national controllability of important data and international position of sovereign currency. Rational design and strategic development are of primary importance under global competition. This paper also provides guidance for the design and development of digital currencies, and further offers policy recommendations under the specific Chinese environment.

Key words: cryptocurrency, digital currency, blockchain, fintech, policy recommendations