3 ms·

>Now back to the original question of whether this could be done with a central database instead of blockchain. The answer is "of course", but now even the who

by simias 9y ago

>Now back to the original question of whether this could be done with a central database instead of blockchain. The answer is "of course", but now even the who and the what is potentially suspect IN ADDITION to the virtual-physical mapping problem. I don't really understand that. The "who" can be authenticated using digital signatures (say, a PGP signature for instance, or a certificate signed by the authority in change). This is exactly the way a blockchain would work, making a transaction means signing it with your private key. As long as your private key remains private nobody can impersonate you (but that's not revolutionary blockchain technology, that's goold old seventies asymmetric crypto technology). As for the "what" I'm not sure what you mean by that. If somebody (the "who") digitally signs a message or transaction and its contents (the "what") gets modified somewhere along the way then the signature will fail to validate. On the other hand if I get a signed message by entity A saying something that turns out to be false then it's proof that A lied, was compromised or made a mistake.

certcomm 9y ago
Yes, you are right. But if you imagine the full provenance of a lot or serial tracked item having hundreds of "messages", it is true they could all be digitally signed by the entities submitting them which would prove "who" sent the "messages". However, keep in mind that all these messages need to be correlated and subject to business logic and validations. For example, the business logic might dictate that one cannot record a temperature reading to the blockchain if the chain-of-custody does not show you as the current possessor of the item. Alternatively, the business logic may say that you cannot blend a non-blendable lot. There are thousands of business rules that need to be enforced along the way. With the (say) PGP approach, you would need to ADDITIONALLY trust that the entity applied these business rules correctly. Also in this approach, there is no single version of the truth. So, every entity maintains its own version of the truth leading to huge synchronization problems in addition to trust problems.
unboxed_type 9y ago
Authentication of a write operation is not the only problem a blockchain system solves. Using a public blockchain, for example, you are assured that: 0) all writes are authenticated 1) all the data written will be accessible to anyone Now contrast it with a centralized solution where admit can just restrict access to some data. Yes, all writes are authenticated, but who cares if you cant access them? 2) The history of all writes is also reliably preserved and accessible to anyone. 3) In case of smart contracts, the business logic is visible to you upfront. You can study the contract and decide if it is fair to participate. You can study the history of that contract also. 4) All "redundant" nodes have proper incentive to participate in the activity. They gain value just by validating and processing your transactions. My point is that this is just not achievable using traditional DBMS: the original premises ("trust model" and incentive model) of those systems are very different. Please correct me if I am wrong somewhere.

by simias 9y ago

certcomm 9y ago

Yes, you are right. But if you imagine the full provenance of a lot or serial tracked item having hundreds of "messages", it is true they could all be digitally signed by the entities submitting them which would prove "who" sent the "messages". However, keep in mind that all these messages need to be correlated and subject to business logic and validations. For example, the business logic might dictate that one cannot record a temperature reading to the blockchain if the chain-of-custody does not show you as the current possessor of the item. Alternatively, the business logic may say that you cannot blend a non-blendable lot. There are thousands of business rules that need to be enforced along the way. With the (say) PGP approach, you would need to ADDITIONALLY trust that the entity applied these business rules correctly. Also in this approach, there is no single version of the truth. So, every entity maintains its own version of the truth leading to huge synchronization problems in addition to trust problems.

unboxed_type 9y ago

Authentication of a write operation is not the only problem a blockchain system solves. Using a public blockchain, for example, you are assured that: 0) all writes are authenticated 1) all the data written will be accessible to anyone Now contrast it with a centralized solution where admit can just restrict access to some data. Yes, all writes are authenticated, but who cares if you cant access them? 2) The history of all writes is also reliably preserved and accessible to anyone. 3) In case of smart contracts, the business logic is visible to you upfront. You can study the contract and decide if it is fair to participate. You can study the history of that contract also. 4) All "redundant" nodes have proper incentive to participate in the activity. They gain value just by validating and processing your transactions. My point is that this is just not achievable using traditional DBMS: the original premises ("trust model" and incentive model) of those systems are very different. Please correct me if I am wrong somewhere.