[Isomatik]

The audit log already exists, or else how would China have found and prosecuted those executives?

The problem at hand is ensuring that the information that makes it on the chain is correct, or at least that other members of the chain have a way of noticing and repudiating that contribution. Cryptocurrency blockchains accomplish this via proof of work and forking, which is why everyone is so interested in the technology. But the only reason they work is that the proof of work mechanism is literally what keeps the network running, and if the network isn't running, all of the sunk costs miners have made are effectively worthless, so even though the miners don't have a reason to trust each other, all of their economic incentives are aligned. The only reason to fork is if you think some people have defeated the proof of work mechanism, or if they are pushing a different version of the blockchain software, which wouldn't be allowed in any real-world application anyway.

Proof of work uses inherently useless calculations to determine that one isn't flooding the network with transactions, because every transaction with a correct key is just assumed to be correct. What real-world application does that map to? Certainly none of the ones in the article, which is why these companies don't use proof of work, they use permissioned blockchains. But a permissioned blockchain is effectively like a standard write-only database with an audit log that each individual in the production line has a password to, which is trivial to accomplish with existing tech. The only way other actors can verify if their peers' inputs to the system are correct is if they verify the physical results, and now we're right back where we started, where you can't trust the system more than you trust any one individual, but now with a db that's at least an order of magnitude slower than any competitive option.

[sho]

I think you explained what I wanted to say better than I said it. Thanks!

[teknologist]

You make a good point, but smart contracts are not just "write-only databases" as they have built-in logic that can bypass some of the need for "verifying peers' inputs" style consensus. For example, attaching a photo of authentic product and being able to check that it on the receiving end could serve as proof that the consumer gets the real deal.

[Isomatik]

Representing a physical product as a unique cryptographic hash that the consumer can independently verify is generally a lot harder than attaching a photo. From a comment below: > Leanne Kemp, an Australian who in 2015 founded a company called Everledger, has now encrypted the distinguishing features of 1.8 million diamonds and their provenance on a blockchain. > More than 40 features are logged to create a fingerprint for each diamond, logging it from mine to ring.

For this to provide proof of authenticity, I need to be able to visit a jeweler not employed by Everledger, and have them be able to use a rubric to classify my diamond along these 40 features in a way that uniquely describes it in a way no other diamond could be described. I then need to be able to visit a second and a third jeweler and obtain the exact same classification along these 40 features.

When visiting Everledger's site, I can't get any information on the classification process beyond that sentence. The supposed core of the product doesn't even have a white paper.

Diamonds are comparatively easy to classify, as they are supposedly unique in many ways, and don't physically degrade over time. When it comes to tins of milk, I can't think of a secure proof of authenticity process that doesn't involve the consumer verifying the composition of the product with a gas chromatography machine.

[teknologist]

Yes, I should have attached a disclaimer that I do not claim that a photograph would be enough to verify the safety of infant formula. Fair points.