That is, "public chain" is the largest number of nodes, in theory, because anyone in the world can participate, block chain data records open, open source code, everyone can access, send transaction requests, and write to the block chain through validation.
Typically, Bitcoin, ETF, etc. Because there are so many participating nodes, it is relatively slow to reach consensus, but because there are so many nodes, it is more difficult to tamper with data. At least, it is possible to tamper with data by controlling more than 51% of the computing resources.
This makes the public chain have the following two characteristics.
1. Open Source: Because the operating rules of the whole system are open and transparent, the system is open source.
2. Anonymity: Because there is no need to trust each other between nodes, and no need to disclose the identity of all nodes, the anonymity and privacy of each node in the system are protected.
The security of public block chains is maintained by "encrypted digital economy", "encrypted digital economy" combines economic incentives with encrypted digital verification by means of workload proof mechanism or equity proof mechanism, and follows general principles: economic incentives available to everyone and tribute to the consensus process. Dedication is proportional. These block chains are usually considered to be "completely de-centralized".
Therefore, relatively mature public chains can best embody the characteristics of block chains, which are safe, transparent and untouchable.
What we call block chains is "value internet", which refers to the functions of public chains.
Current status of public chain: nearly 4 billion Internet users worldwide, but less than 20 million public chain participants in the current block chain, the application is very single, and the scope of service is limited. In addition, block chains are used in the "digital society". In 2017, the global data volume is about 23 billion TB. At present, the most abundant public chain in the market is Ethernet workshop, and the data processed is less than 1 TB.
So that's why there are so many public chains in the market that claim to subvert ETF.