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What you've described is provenance I believe. And that is the only, imho, use case for blockchain that makes any sense. It's the only one where the substantia

What you've described is provenance I believe. And that is the only, imho, use case for blockchain that makes any sense. It's the only one where the substantial additional overhead and complexity of blockchain is actually still less than the alternative, as your example clearly illustrates. To attempt to answer a question from sibling comments: these systems are private or closed blockchains, not public. You have a traditional credentials database (the blockchain itself could also be used for this, but that won't usually have inherent benefits) to track who is allowed access to read or submit transactions. Those parties may run a node or you may have one independent third party run all the nodes. It's so different from cryptocurrency setup that it's hard to apply too much of the stuff we've learned from Bitcoin et al to these setups. At least that's my understanding.

donmatito 9y ago
I feel like a private/closed blockchain would defeat the purpose. I want a future where a public blockchain would act a repository of everything that has happened to the final product throughout its history, on top of which applications would be developped, relevant for each step of the chain. The producer A that would input certification of origin, the manufacturer B, and the end consumer C would need very different services, web, app, industrial applications, ERP integrations and so on. To express it in an analogy with current services, I would like the blockchain to be a database, exposing a universal API. I don't really see a private blockchain allowing this, but I may be wrong. And indeed there will be the thorny authentication issue... I don't know the solution, really !
s73v3r_ 9y ago
So why use a blockchain instead of a regular database?
filleokus 9y ago
If we imagine the best-case scenario, where all actors are handling their keys with care, and a system works to somehow produce an immutable, always consistent log of all actions, I still don't see how this will be usable for most products. You basically also need an immutable link between the physical product and some kind of cryptographically provable ID in this magic log. When receiving an item you want to check the provenance of, you need some way to securely identify the product in the log. Otherwise some bad actor along the way could unlink the actual product from the ID in the log, for example by duplicating and stealing a known-good ID, yielding all the provenance information useless. I guess this could work for electronic products where you could deeply embed something like a TPM that could provide this ID securely (which would be to expensive to extract to make it worth duplicating), but for something like a shipment of steel or even worse coal/oil/grain etc, I don't see how this would work.
- glitch003 9y ago
  A simple SIM card or smart card is a suitable TPM for this, and can be obtained for pennies on the dollar.
  - ytpete 9y ago
    The poster's point is that the link between that and the actual object of value is a huge weak point. Let's use expensive art as an example since it's such a commonly cited use case. Blockchain says I own an original Picasso painting. You pay me 1 BTC in exchange for me transferring ownership of the painting to you: blockchain says the painting is now yours, _and_ I have to ship you the physical painting so you can hang it in your house / art gallery / whatever rich people do with art. The problem is, how do you know I didn't ship you a fake replica and keep the original for myself, sell it to someone else on the sly, etc.? Sure, you could have a TPM which securely holds some data linking the physical smart card to the blockchain provenance record... but what links the physical smart card to the physical painting? Couldn't I just give you the fake painting + real smart card? You could get an art expert to authenticate the physical painting, of course -- but that's exactly the same reliance on a trusted third party that art collectors have today, and blockchain has done nothing to improve the situation...
- donmatito 9y ago
  I agree, that's the issue. I suppose it will depend on the application need, and the criticality. If you need to prove that life-saving drugs have been kept at the correct temperature throughout their shelf-life, you can probably afford a RFID tag per pack, with a unique ID. On the other end of the spectrum, if you are talking about low-criticality tracability of shipments of bulk materials, you can probably admit supplier-defined batch numbers. You could imagine that a rogue manufacturer would try to cheat and re-use a batch number from a "premium" raw material while using a cheaper one. Blockchain would not provide a protection against false declaration, it would on the other end provide an immutable papertrail in case of later legal investigation / certification audit (ie "you purchased X premium parts and Y inferior parts, but you logged using X+Y premium parts, how do you explain that?")

donmatito 9y ago

I feel like a private/closed blockchain would defeat the purpose. I want a future where a public blockchain would act a repository of everything that has happened to the final product throughout its history, on top of which applications would be developped, relevant for each step of the chain. The producer A that would input certification of origin, the manufacturer B, and the end consumer C would need very different services, web, app, industrial applications, ERP integrations and so on. To express it in an analogy with current services, I would like the blockchain to be a database, exposing a universal API. I don't really see a private blockchain allowing this, but I may be wrong. And indeed there will be the thorny authentication issue... I don't know the solution, really !

s73v3r_ 9y ago

So why use a blockchain instead of a regular database?

filleokus 9y ago

If we imagine the best-case scenario, where all actors are handling their keys with care, and a system works to somehow produce an immutable, always consistent log of all actions, I still don't see how this will be usable for most products. You basically also need an immutable link between the physical product and some kind of cryptographically provable ID in this magic log. When receiving an item you want to check the provenance of, you need some way to securely identify the product in the log. Otherwise some bad actor along the way could unlink the actual product from the ID in the log, for example by duplicating and stealing a known-good ID, yielding all the provenance information useless. I guess this could work for electronic products where you could deeply embed something like a TPM that could provide this ID securely (which would be to expensive to extract to make it worth duplicating), but for something like a shipment of steel or even worse coal/oil/grain etc, I don't see how this would work.

glitch003 9y ago
A simple SIM card or smart card is a suitable TPM for this, and can be obtained for pennies on the dollar.
- ytpete 9y ago
  The poster's point is that the link between that and the actual object of value is a huge weak point. Let's use expensive art as an example since it's such a commonly cited use case. Blockchain says I own an original Picasso painting. You pay me 1 BTC in exchange for me transferring ownership of the painting to you: blockchain says the painting is now yours, _and_ I have to ship you the physical painting so you can hang it in your house / art gallery / whatever rich people do with art. The problem is, how do you know I didn't ship you a fake replica and keep the original for myself, sell it to someone else on the sly, etc.? Sure, you could have a TPM which securely holds some data linking the physical smart card to the blockchain provenance record... but what links the physical smart card to the physical painting? Couldn't I just give you the fake painting + real smart card? You could get an art expert to authenticate the physical painting, of course -- but that's exactly the same reliance on a trusted third party that art collectors have today, and blockchain has done nothing to improve the situation...
donmatito 9y ago
I agree, that's the issue. I suppose it will depend on the application need, and the criticality. If you need to prove that life-saving drugs have been kept at the correct temperature throughout their shelf-life, you can probably afford a RFID tag per pack, with a unique ID. On the other end of the spectrum, if you are talking about low-criticality tracability of shipments of bulk materials, you can probably admit supplier-defined batch numbers. You could imagine that a rogue manufacturer would try to cheat and re-use a batch number from a "premium" raw material while using a cheaper one. Blockchain would not provide a protection against false declaration, it would on the other end provide an immutable papertrail in case of later legal investigation / certification audit (ie "you purchased X premium parts and Y inferior parts, but you logged using X+Y premium parts, how do you explain that?")