Comment by Terr_

Like when people discuss voting, I believe a blockchain [0] is a terrible pitfall compared to a classic distributed database system of predefined nodes run by different organizations. For example, imagine a couple hundred predefined nodes run by different states, federal agencies, etc.

An attacker altering the ledger would still require compromising an unreasonably large number of independent groups at once, and even then the rest would be able to clearly see that some unusual and suspicious event occurred.

By limiting membership a bunch of problems simply vanish, like long-clearing times, wasting hardware on mining, vulnerability to foreign botnets, etc.

[0] A blockchain is distinguished by its core requirement, from which a cascade complexity flows: Uncontrolled node membership. Don't be fooled by people pitching "private blockchain", its a contradiction in terms designed to rehabilitate hype, like "multi-sample Theranos test" or a bicycle as "Segway passively stabilized inline wheel model."