[kccqzy]

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?

[Donzo]

All of the censors vote on if they have been tampered with. They will leave a record of their votes on the blockchain as Bob tampers with them in real time.

[vertex-four]

So Bob tampers with them all to record “everything’s fine” all the time. What now?

[Donzo]

Finally! He can melt all the ice-cream and destroy his customer.

No, Bob's misconduct would potentially be provable in court based on the trustless data ledgers in the blockchain.

Really, this example just shows one way how developers could use blockchain technology to develop applications that utilize trustless data.

Imagine this same technology applied to the transfer of human organs, rather than easily replaceable ice cream.

Challenge yourself to think of other scenarios in business where trustless data might make a difference.

Maybe you'll have a valuable idea in this wide open space.

[winslett]

I’ve heard many scenarios like “transfer of human organs” as a scenario for blockchain, but I’m skeptical that blockchain solves problems in the tangible world all that easily. It is my perception that blockchain is great for trustless information assets, but not great for trustless tangible assets.

Blockchain can’t stop a human from stealing an organ and replacing it with a different organ. Even tracking shipping containers, which was high profile a few years ago, only requires a human to make a mistake in loading a boat to throw off the database.

In tangible-world-to-information-storage scenarios, the hard part is not the information, but the guarantee that information matches the real world. In my view, the claim that blockchain solves for a trustless tangible world is naive.

[Donzo]

It's hard to imagine a solution to these problems because we are so far away from highly functional examples of this tech in action in the "real" world.

That said, engineers live to solve problems in better, smarter ways.

I personally believe it is naive to bet against innovation in this sphere, but we both shall see if we are so fortunate.

[vertex-four]

If you have trust in a court, you don't need a trustless system, by definition.

[Donzo]

Slippery slope: I can trust the court if I don't have to trust the data. I can't trust the court if I have to subjectively prove my arguments.

[vertex-four]

But you can't trust the data if the systems providing - creating - that data are tampered with, by definition!

[cdetrio]

Its easy to go through a couple containers and find/replace a few sensors. But it would be a lot of work for Bob to go through every single yogurt container and corrupt all the sensors.

[dragandj]

Hmmm. But, how does a distributed blockchain help anyway?

[wsxcde]

The assumption is that there are only "a small number of faulty or corrupted sensors."