I appreciate the effort in writing this readable paper, but I do find the analogies in the first few sections to be quite strained.

Here's an example:

> Alice decides it is time to blockchain her supply chain. She rents some cloud storage to hold the ledger, and installs internet-enabled temperature sensors in each frozen yogurt container. She is concerned that sensors are not always reliable (and that Bob may have tampered with some), so she wires the sensors to conduct a Byzantine fault-tolerant consensus protocol, which uses several rounds of voting to ensure that temperature readings cannot be distorted by a small number of of faulty or corrupted sensors.

Now, since all frozen yogurt containers pass from Carol to Bob to Alice, doesn't Bob at some point in time have access to all the frozen yogurt containers and their temperature sensors? Then Bob can easily corrupt all of them, rendering this scheme useless. He can, for example, replace all of the sensors by malicious sensors that report wrong temperatures when they are in Bob's truck.

Is there something I'm missing?