Dos and Don'ts in Blockchain Research and Development.

The goal of this paper is to clarify common misconceptions regarding the blockchain technology, and pointing out some worrisome practices in the field of blockchain technology. We first provide a brief introduction of the blockchain technology, highlighting its design principle, nuts and bolts, and the most fundamental innovation of the technology. Next, we elaborate on a key concept regarding data immutability. In particular, it is a mistake to equate blockchain to data immutability. Data immutability can only be achieved in large-scale public blockchains where the cost becomes an insurmountable barrier for any attempt to change the data recorded in the blockchain. The third topic we discuss is the differences between public, private, and consortium blockchains. We caution the use of private and consortium blockchains. The last topic we argue is regarding blockchain consensus. Because the proof of work (PoW) consensus algorithm has obvious drawbacks on energy consumption, many alternative algorithms have been proposed. We single out two most egregious wrong practices: (1) selecting a small set of validators for reaching consensus, and (2) adopting traditional distributed consensus.