So. I, person A, am putting a part up for sail with "omitted details like final prices or provenance documents." How does blockchain solve this problem?
I, person B, am buying that part. Then I'm putting it up for sale again with a different set of details and provenance documents (because I'm a fraud or because I don't have any other documents). How does blockchain solve this problem?
Obviously a blockchain cannot magically make people do things they don't otherwise want to do.
But what a blockchain can do is model parts as tokens that can only exist once on the chain, associate data like provenance documents with each token, then model sales as transfers of the token. Finally, it can do all that in a way that you don't have to trust any single entity (though you might have to trust the consensus of a large number of entities; this is better because pressuring many entities to lie is much harder than pressuring one to lie).
Whether this particular blockchain uses that design is a separate question. I agree that if your trust model isn't distributed, a simple database will usually be better.
> Obviously a blockchain cannot magically make people do things they don't otherwise want to do.
So, what's the point, really, especially if talk about "Distributed trust" if blockchain provides nothing to ensure that trust?
> But what a blockchain can do is model parts as tokens that can only exist once on the chain, associate data like provenance documents with each token, then model sales as transfers of the token... a way that you don't have to trust any single entity
So, the details and provenance magically appear on the blockchain. Who verifies them? Who makes sure they are complete? Let me guess, some centralised/external entity?
So, there's some part associated with a token. What's to stop me from associating the same part with a different token? Or with 100 tokens? I'm guessing there is some centralised agency that verifies that a part is associated with a token through the part's serial number and that: a) no other token is associated with the same number and b) the seller associates serial numbers, and not some random numbers with the token?
I'm not even going into such things as "seller A sold part B to buyer C, received the money and never sent the part", let's start with documents, parts, tokens and associations.
Yes, you need a trusted path to go from physical reality to the token on the blockchain. But blockchains let you shrink that path down to a small number of operations that can be closely scrutinized. (This is how blockchains are similar to cryptography, where the goal is to secure a large amount of data by keeping a small amount of data secret.)
As far as how to build that trust goes, what you're talking about is similar to the certificate signing problem. There are at least two ways to do this — a hierarchy trusted by everyone (akin to PKI) and a decentralized web of trust. Blockchains let you do either or both of those things since entities can sign off on the provenance on the blockchain. You can also have multiple entities sign off on it, similar to GPG keys.
> Yes, you need a trusted path to go from physical reality to the token on the blockchain.
You mean a centralised entity that is able to verify all claims input on the blockchain, cross-reference these inputs, and then enforce the execution of the contract.
Why would you need blockchain then if you trust such an entity with so much more than just with part tracking?
> Blockchains let you do either or both of those things since entities can sign off on the provenance on the blockchain.
wat
> You can also have multiple entities sign off on it, similar to GPG keys.
So, blockchain "solves" exactly one thing: inventory tracking. And does it in an overly complicated and highly inefficient way. Everything else is entrusted to external entities.
To quote an amazing article [1]
--- start quote ---
People treat blockchain as a “futuristic integrity wand”—wave a blockchain at the problem, and suddenly your data will be valid. For almost anything people want to be valid, blockchain has been proposed as a solution.
It’s true that tampering with data stored on a blockchain is hard, but it’s false that blockchain is a good way to create data that has integrity.
Blockchain systems do not magically make the data in them accurate or the people entering the data trustworthy, they merely enable you to audit whether it has been tampered with.
How then, is trust created?
... if you look at any blockchain solution, inevitably you’ll find an awkward workaround to re-create trusted parties in a trustless world.
The article is correct that you still need oracles (of course you do), but wrong in saying that blockchains are therefore useless.
A better article would be more intellectually curious! For example, it might talk about the sorts of oracles blockchains could enable and how much of a burden they need to bear with and without blockchains.
Shouldn’t blockchain proponents be the ones to come up with such an article?
The article specifically calls out all the use cases for which blockchains have been proposed as a solution. And none of those solutions discussed the need for oracles or discussed “what sorts of oracles they would enable”.