
Ask HN: Can a blockchain do this? - data37
I&#x27;m checking if a blockchain is applicable to our project.<p>In our requirement, a supplier and a buyer get into a work agreement. Later, supplier could claim that they have delivered according to the contract. But buyer could say that the delivery did not meet the quality norms as per the agreement.<p>I guess such situations are taken to court if big money is involved. Instead, can a technical solution such as blockchain resolve such issues? How can a blockchain verify if the quality of the delivered goods or work meets the terms in a smart contract? If not, what good can we expect from a smart contract and blockchain for this context?<p>Thanks!
======
gus_massa
Let's suppose that A has to deliver chocolate icecream to B. How can a
blockchain verify if the quality of the delivered icecream??? Is the chocolate
concentration right? Is the quality of the chocolate good? More difficult, did
it arrive melted or too frozen?

I think it's possible to use multisignature transactions to implement an
escrow service that can arbitrate in case of a dispute an send forward or
backwards the money. (If the buyer and seller agree, they can complete the
transaction automatically.) But you are changing a court in the real word by
some arbiter in the real word.

Anyway, I'm not sure if someone has a good working scheme like this.

------
davidgerard
tl;dr:

* A blockchain is never the answer in the general case.

* smart contracts require programmers to not only write bug-free code the first time (c.f. The DAO), not only make sure bugs in the underlying platform don't bite them (c.f. The DAO), but make sure the circumstances the contract runs in never change.

* even Vitalik Buterin notes that smart contracts are an equivalent problem to strong AI in the general case [https://blog.ethereum.org/2016/06/19/thinking-smart-contract...](https://blog.ethereum.org/2016/06/19/thinking-smart-contract-security/)

* the actual problem you state here is entirely to do with human perceptions and how they feel about the quality of the work. I assume you're looking for a cheaper alternative to argument and disagreement. But ultimately you're looking at lawyers, courts and/or some sort of human-mediated arbitration just from your problem as stated.

------
namecast
You may want to look into the 2-of-3 escrow with timeout defined in BIP 112.

[https://github.com/bitcoin/bips/blob/master/bip-0112.mediawi...](https://github.com/bitcoin/bips/blob/master/bip-0112.mediawiki)

You want 'the blockchain' to verify payment between parties; these parties
will be in charge of verifying satisfactory delivery and releasing funds.

