What is digital currency？

Digital currency is a kind of electronic currency created, issued and circulated by means of check and password technology. For example, bitcoin, lightcoin and bitstock are digital currencies created, distributed and maintained by cryptography and verification technology. The characteristic of digital currency is that it uses point-to-point technology and everyone can issue it.
In the stage of blockchain 1.0, the application scope of blockchain technology is mainly concentrated in the field of "digital currency". After bitcoin was launched in 2009, because bitcoin blockchain solved the "double flower problem" and "Byzantine general problem", and really cleared the main obstacles of "digital currency" circulation, it gained great popularity, and "Fraud" and "digital currency" such as dogecoin and Leyte coin also began to emerge in large numbers. These "digital currencies" are very similar to bitcoin in technology, and their architecture can be generally divided into three layers: blockchain layer, protocol layer and currency layer. As the underlying technology of these "digital currency" systems, the blockchain layer is the most core part. The core functions of the system, such as consensus process and message delivery, are achieved through the blockchain. The protocol layer mainly provides some software services for the system, makes rules, and so on. The last currency layer is mainly used as value expression, which is used to transfer value between users, equivalent to a monetary unit.