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Ask HN: What are real-life useful use-cases for blockchain (not currencies)?

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Re: Ask HN: What are real-life useful use-cases for blockchain (not currencies)?

#181

Post by sebmellen »

rebelos wrote: post #136
snarf21 wrote: post #106

Earlier quoted context omitted.

Sorry, but your solution solves nothing. The transporter could take a picture of the odometer and tweak the image. Your solution is only as secure as the input flow and you can't control it. A blockchain can't reflect physical reality. It can only reflect what someone said/says physical reality is. Additionally, they have to trust you to push the "right" data to the blockchain. If they are already trusting you, you c…

I would just like to say that if anyone has a rational counterargument to this, I really want to hear it. This is precisely the observation past which the logic becomes less coherent in just about any conversation I've had on blockchain applications.

Please see my comment in response to the grandparent comment. I think it will address your concerns with a rational counterargument.

Basically, yes, you could, in theory, maybe, sort of, possibly, build a similar system without a public blockchain. But why? I'm sure there are people who can build houses with a few hand tools, but there's a reason we have power tools and heavy machinery — they are more efficient and fit the job better. The same goes for blockchain in this case.

If you can point out where my logic is incoherent, please do, but to me the following: "oh, just set up a distributed git repo or database with checksums and append-only permissions that you control but replicate to other servers not controlled by you so that you can't tamper with the outputs and read from that global state and verify against the other mirrors of the database or repo every time you read from global state" sounds like a stupider alternative to blockchain.

This is what blockchains were made for!!! Distributed consensus!

Re: Ask HN: What are real-life useful use-cases for blockchain (not currencies)?

#183

Post by sebmellen »

smt88 wrote: post #101
sebmellen wrote: post #7

The biggest use case I have found of blockchain tech is timestamping, especially in a case where the timestamping party cannot be trusted to act honestly because of conflicting interests. I'll give you an example, from one of my startup's enterprise customers. This company needs to ensure that their high-end auto inventory remains in the same state through transport — the mileage, the car body, etc. They've had issue…

> where the timestamping party cannot be trusted to act honestly because of conflicting interests But in this case, isn't whoever controls your code the "timestamping party"? Looking at two examples: A: With blockchain The timestamp that the photo was taken is immutably, publicly logged. B: Without blockchain The timestamp the photo was taken is logged by you, the software provider. What is a scenario where (B) is le…

To address your concerns:

> isn't whoever controls your code the "timestamping party"?

No (and sort of yes). The result of the timestamp is instantly verifiable against the timestamped data, meaning the results of the timestamp can be viewed on a public blockchain explorer or using an API that interfaces with the blockchain, without trusting our code. If another party doesn't trust our frontend code, they can build their own frontend logic that interfaces with the blockchain in the backend to independently verify results. If someone is using our app, they implicitly trust our code, yes, but they don't have to trust our database. That's the difference.

> In both scenarios, you have no proof of when the photo was taken. It could've been two hours or ten minutes ago. There is no way to digitally verify it.

This is a solvable-ish problem. What our app does is require the photos to be taken in-browser, and adds a small stamp to the photo before hashing it with the most recent Bitcoin block hash. This way, we have a window of ~10 minutes within which we know the photo was taken.

Can this be abused? Yes. But the transporter is exceedingly unlikely to know how, and they also don't have access to the cars before handoff, so the concern is really negligible. Faking the photos is now at least a few order of magnitudes harder than before. We can improve on this in the future.

> posting a photo of a different vehicle

We ask the transporters to take a photo of the VIN in the frame, along with other photos (body, odometer, etc.). This is a pretty foolproof solution.

Re: Ask HN: What are real-life useful use-cases for blockchain (not currencies)?

#184

Post by sebmellen »

bb88 wrote: post #129
smt88 wrote: post #101

Earlier quoted context omitted.

> where the timestamping party cannot be trusted to act honestly because of conflicting interests But in this case, isn't whoever controls your code the "timestamping party"? Looking at two examples: A: With blockchain The timestamp that the photo was taken is immutably, publicly logged. B: Without blockchain The timestamp the photo was taken is logged by you, the software provider. What is a scenario where (B) is le…

The picture of the car is not protected by hard crypto until it's inserted into the blockchain. Until it is inserted the trust chain breaks at the questions of: When was it taken? Who was taking the picture? What is the picture of? The car to be protected? Or someone else's car. Blockchain works for currencies, since currencies are just numbers in a ledger. And numbers can be easily secured with strong crypto.

See my response to the grandparent comment for more details.

> When was it taken?

We currently verify this by including the last Bitcoin block hash in the photo, giving us a ~10 minute time window in which the photo was taken. Also, the whole handoff period is under 20 minutes, so the transporter only has access to the cars for 20 minutes (with many others around), before a timestamp is required.

> Who was taking the picture?

We've never run into this as a problem, but we can require a continuous video including a selfie of the transporter.

> What is the picture of? The car to be protected? Or someone else's car.

This we verify by checking the VIN in the frame (frame number check).

Re: Ask HN: What are real-life useful use-cases for blockchain (not currencies)?

#185

Post by sebmellen »

vinni2 wrote: post #96
sebmellen wrote: post #7

The biggest use case I have found of blockchain tech is timestamping, especially in a case where the timestamping party cannot be trusted to act honestly because of conflicting interests. I'll give you an example, from one of my startup's enterprise customers. This company needs to ensure that their high-end auto inventory remains in the same state through transport — the mileage, the car body, etc. They've had issue…

How do you trust the source of the timestamp used for the pictures? I am assuming the clock on the camera is not synchronised with all nodes participating in the blockchain. May be I misunderstood the application. Edit: synchronising clocks is one of the hard problems in distributed computing https://en.wikipedia.org/wiki/Clock_synchronization

The trusted source of time is the Stellar blockchain, and the last Bitcoin block hash, giving us a ~10 minute period wherein the photo must have been taken. Essentially, we abstract the time synchronization issue away from the photo taker to an external trusted source.

The Bitcoin block hash cannot be known before it's calculated, and a new one is calculated every 10 minutes. Works great.

Re: Ask HN: What are real-life useful use-cases for blockchain (not currencies)?

#186

Post by sebmellen »

smt88 wrote: post #160
poiuiopkj wrote: post #94

Earlier quoted context omitted.

The next entity in the supply chain would have an odometer that didn't match the picture that was previously posted. It limits who is possibly at fault to a minimum of one of two parties, which I'm sure could be narrowed down further by corroborating evidence. It highly discourages it because at the very least, you would be the first suspect with no real finger to point.

That's true, but none of that is enabled by blockchain. You can do all of that with an append-only, distributed database that is cryptographically verifiable. You don't need a public blockchain (or any blockchain at all).

> an append-only, distributed database that is cryptographically verifiable

You just described a blockchain. Why rebuild what already exists? A blockchain is a great drop-in solution and reduces our costs and implementation worries massively. And the distribution of this public blockchain is much more decentralized than we could ever achieve running our own nodes.

Re: Ask HN: What are real-life useful use-cases for blockchain (not currencies)?

#187

Post by lancewiggs »

geofft wrote: post #99
scubbo wrote: post #97

(Disclaimer - I believe myself to have a better idea of what a blockchain is and how it works than the average layman, but I'm certainly not an expert) Having recently completed a house purchase and waded my way through reams of paperwork in the process, I'm stunned that there's no "document provenance chain" implementation. At every stage of the process, I was presented with tens or hundreds of pages of paperwork th…

Right, all you need is a hashed object that includes the hash of the previous version. Git / most DVCSes are built on this but even they are more complicated than what you need. What you actually want, I think, is a legal document that says "The parties hereby amend the contract previously agreed to on mm/dd/yy as follows: after paragraph 5, add .... For reference, a full copy of the amended contract is included. In…

The contracts (for any commercial transaction) are not agreed until they are finally signed. Until then the contracts are being amended by the parties, and generally with tracked changes.

Re: Ask HN: What are real-life useful use-cases for blockchain (not currencies)?

#188

Post by xupybd »

snarf21 wrote: post #106
sebmellen wrote: post #7

The biggest use case I have found of blockchain tech is timestamping, especially in a case where the timestamping party cannot be trusted to act honestly because of conflicting interests. I'll give you an example, from one of my startup's enterprise customers. This company needs to ensure that their high-end auto inventory remains in the same state through transport — the mileage, the car body, etc. They've had issue…

Sorry, but your solution solves nothing. The transporter could take a picture of the odometer and tweak the image. Your solution is only as secure as the input flow and you can't control it. A blockchain can't reflect physical reality. It can only reflect what someone said/says physical reality is. Additionally, they have to trust you to push the "right" data to the blockchain. If they are already trusting you, you c…

It makes it hard to alter historical data. It does not prove the data was correct to begin with. Blockchain isn't the only way to do this but it is a good way if you don't trust the parties holding the data not to attempt to alter it. You could avoid that by holding your own copy of the data and checking against that. What solution is best depends on the situation.

Re: Ask HN: What are real-life useful use-cases for blockchain (not currencies)?

#189

Post by vmception »

FridgeSeal wrote: post #127
mareko wrote: post #114

Venmo for all. We're used to Venmo in the US but many places in the world don't have an equivalent. Valora is a new Venmo-like mobile app that's built on the Celo blockchain, a new network where mobile devices can efficiency sync with the chain, with a native stable coin, and a decentralized phone number verification protocol. Check out https://valoraapp.com and https://celo.org

In my country this is already fully supported: PayID will let you transfer money instantly instantly between accounts (up to some daily limit), with no fees. Similarly, an app called BeemIt, which is supported by the major banks here gives you a very similar experience, albeit with a prettier UI/UX. As it stands, there’s now no advantage that cryptocurrency offers in this space anymore IMO.

blockchain for no limit then.

Re: Ask HN: What are real-life useful use-cases for blockchain (not currencies)?

#190

Post by vmception »

The consensus models without the payment mechanism all undermine the utility of a blockchain.

Proof of Work and currency are inseparable, it is all interrelated to the design of any application using the blockchain.

I used hyperledger and even the example projects from the instructor were talking about all the threaded operations it can do, if there is no cost to the computation then randoms are DDOSing all the nodes in the system for no reason, which is exactly what happenes in real world hyperledger consortiums. Its dumb.

Either accept that speculation is a use case or move on.

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