Wowing govt officials and scamming public money.

Sometimes it's the government's idea in the first place. I work at a contracting company, and one of our government customers said they wanted a service that utilized blockchain technology. They didn't know what a blockchain was, or care what the blockchain powered service was, they just wanted to sound like they were responsible for acquiring cutting edge technology. Luckily that was shortly before NIST put out their research paper that said there is almost never a good reason to use a blockchain, and the government employee quickly lost interest.

Link to the said paper, please?

Probably means this one from 2018:

https://nvlpubs.nist.gov/nistpubs/ir/2018/NIST.IR.8202.pdf

Brief quote from the conclusions:

> The use of blockchain technology is still in its early stages, but it is built on widely understood and sound cryptographic principles. Currently, there is a lot of hype around the technology, and many proposed uses for it. Moving forward, it is likely that the hype will die down, and blockchain technology will become just another tool that can be used.

Then there is a fairly large paragraph about limitations and choosing the right tool for the job rather than just trying to shoehorn blockchain in for its own sake.

Blockchains are an irrevocable proof of record (immutability with cryptographic proof) unlike traditional databases that need to be audited to capture all updates. Amazon QLDB, though private but not a Blockchain, could be used as one: For ex, creating and maintaining customer wallets (per customer coupons and discounts specific to your service).

Public blockchains could be used for accounting transparency, for example, for tracking donations and spends of a non-profit. Decentralised blockchains are of course being continually redefined and reinvented, with an alternate financial complex at the forefront of it all.

There are likely many more usecases, but the ones most interesting to me are global payments infrastructure being built by stellar.org, celo.org, and diem.com.

See also: https://www.hyperledger.org/

What is the advantage of a private blockchain over a hash tree like used in git? A git commit is also irrevocable, except if you do a git rebase. How do you prevent something similar like a git rebase in a private blockchain?

A public blockchain with multiple agents that do not trust each other like in BitCoin make sense to me.

Think of an industry e.g. like banking, where the different participants know who each other are but don't fully trust each other. Presuming each participant controls one replica in the system, then using BFT algorithms you can ensure that so long as less than a third of the participants are malicious it is not possible to perform such an attack.

You can also set up a git repository and prevent history rewrites on the central server. Some third party could also offer this as a service. Each entity can check this by doing a pull every minute in a cron job, which fails when history rewrite happened. If they detect this, their legal department can take some actions.

Just because Encarta existed, didn't mean Wikipedia shouldn't; or because NFS exists, Dropbox shouldn't. They can be solutions to the same problem. In git's case though, it sounds more like a abuse of its underlying properties (not to mention, you'd have to block all git commands that can rewrite history).

> not to mention, you'd have to block all git commands that can rewrite history

Okay, so use mercurial or fossil.

Don’t signatures get you the same benefit? I don’t need to trust you simply to sign something saying “user X showed me hash Y at time Z”.

Signatures still requires a centralized entity to manage the trust. A public distributed ledger, be it a blockchain or something else do not.

We don't even have a centralized authority for x509 in browsers, and that's the closest you come to being correct — there are still many CAs and multiple groups coordinating which of those are trusted, and private CAs are common even up to millions of users.

GPG has been around since the 1990s with the web of trust being entirely decentralized and while I'd be the first to say there is room for improvement there's no way that's anything other than decentralized.

Don't a private blockchain need that anyway to manage access to add to the chain?

Or how does a private blockchain manage who has write access to it (since it's supposed to be private)?

>an irrevocable proof of record (immutability with cryptographic proof)

Which ignores and can even make worse the problem of bad data at the entry point. This is what effectively killed the entire set of use cases related to supply chain provenance.

But how can a blockchain be actually and meaningfully "public" without proof of work and distributed mining establishing majority based consensus on what _is_.

If you just store the equivalent of a blockchain somewhere then I don't see what benefit it provides over a database controlled by a consortium.

It's all bullshit.

Presumably, there's a third party that keeps a copy of the blockchain. If you rewrite the history of your blockchain, they'll detect it.

It's fair to ask why this public record needs to be in a blockchain though. You could store the record in plain HTML on a public website and have the Web Archive create periodic immutable snapshots of it.

Exacactly - you just need something equivalent to a certificate authority which signs states of the database and guarantees the correctness of the stored data.

For more than a decade, this company has been publishing their hashes in the NYTimes classified ads: http://www.surety.com/digital-copyright-protection/prove-own...

(some cryptokiddies have tried to claim it as "the world's first blockchain" https://btcmanager.com/finding-the-oldest-blockchain-in-the-... apparently not understanding how much it undermines the case for wasteful proof-of-work blockchains if a classified ad does the same job)

Okay, and what happens when I run a phony ad next to this one in the New York Times? What happens when I bribe the guy at the Times to accidentally use my hash rather than theirs?

It’s a cute gimmick, I’ll give them that.

They prove that the hash they publish in the NYTimes exists at that time. There are probably some archives which can give you an authorized copy of the NYTimes from a specific date. You can use that to prove that the hash existed at the date the NYTimes was published. This is now the hash over a hash tree, which this companies stores. With this single hash they can also prove that every document in this hash tree existed at that time. They can not add a extra document later, because this would alter the hash they published in the NYTimes.

When you publish your phony ad in the NYTimes, you also prove that this phony ad existed at the date the NYTimes was published.

This company probably buys one edition of the NYTimes with their add and check if the NYTimes published the correct hash, if it is wrong they will run an other add the next day with the correct hash the next day. Now they only prove that the hash existed the next day.

The NYTimes hashes idea is brilliant, but if you were to try to scale that concept to thousands or millions of different global use cases, eventually it seems like you'd end up with a technology platform similar to a public distributed ledger, i.e. a blockchain.

I'm open to hearing about any other non-blockchain solutions to this problem, though. One seems to be IOTA and their "Tangle" graph, but I don't fully understand how that could facilitate a historical record of each transaction, as (unlike a blockchain) it is not an append-only ledger.

That requires trusting one authority. You can do better - there are distributed algorithms that can prevent malicious behaviour from compromising the system so long as less than a third of the participants are malicious.

A blockchain requires trusting the authority that set it up and/or any authority that can 51% attack it.

If you are in a situation where you can't find any trustworthy authority (including yourself), you are probably part of a scam or a crime.

Byzantine fault tolerance is an interesting concept that solves a problem that almost never happens in modern software.

> A blockchain requires trusting the authority that set it up and/or any authority that can 51% attack it.

So, you don't understand how blockchains work, okay.

With a distributed BC you don't have to trust an authority. You trust that 51% of participating entities know what they are doing and that they checked the protocol implementation and agree on one.

A distributed blockchain has code that you have to trust.

Also you can say that everything in a blockchain is verifiable by third parties, but most people don't do that work (not unlike any open-source software).

I don't know why the comment above was downvoted. The parent clearly doesn't know what they are talking about (e.g. in a deterministic setting at most one third can be malicious).

A distributed ledger eliminates the risk that the third party hosting the record can be hacked or that the operator fraudulently lies in the record.

A blockchain does not require anything beyond ensuring the prior entries checksums make sense.

Making past entries immutable is the purpose.

Proof of work and distributed mining don’t need a blockchain.

Have you heard of hashcash? It is proof-of-work concept to prevent email spam.

https://en.m.wikipedia.org/wiki/Hashcash

what prevents the entity controlling the blockchain from recursively changing data and adjusting the checksums?

Paraphrasing Achebe here: “that until the lions have their own historians, the history of the hunt will always glorify the hunter.“

This is also an issue with a 51% attack.

Proof of work is fading away, Proof of Stake is becoming the default method.

See my answer above - in cases where the participants are all known you can use BFT algorithms to prevent attacks so long as less than a third of the replicas are malicious.

Every company on the planet seems to be asking that. It’s like “AI”, one of those technologies that you can’t risk everyone else using while you don’t.

So for some reason having a solution and look for the problem is suddenly acceptable. Few seem to find the problem though.

If you read through typical descriptions of how blockchains can be applied in industry, you’ll notice that they are extremely vague. That should tell you something.

Ummm Vet? Theta? Real worlds solutions to supply chain and video streaming, respectively.

Public relations, mostly.

NY runs its Vaccine passport on an IBM blockchain citing privacy benefits:

>special emphasis has been placed on the protection of an individual's privacy. Secure technologies, like blockchain and encryption, are woven throughout Excelsior Pass to help protect the data, making it verifiable and trusted. No private health data is stored or tracked within the apps. Excelsior Pass can be used to voluntarily show a QR code as proof of COVID-19 vaccination or negative test result via a digital smartphone wallet or printed credential without sharing underlying personal health details.

https://www.governor.ny.gov/news/governor-cuomo-announces-la...

No one, other than the city of NY, will have the full node.

So in this use-case there is no distributed network in the first place. And never will be.

Reading through both that and IBM's site, I'm struggling to see how blockchain enables this in any way? Covid test and vaccine providers have to be trusted for any of that to work, and without the "trustless" element blockchain provides you literally zero advantages (with a huge amount of disadvantages).

EDIT: I guess I could request the whitepaper from IBM and read it, I mean what's yet one more tech giant sending me spam and selling my info to advertisers going to hurt? But I don't see any way for the entire thing to work and avoid people making up fraudulent test results/vax records without trust. I mean even with trust a clinic could feasibly fake that stuff, but without trust pretty much anyone could do it.

EDIT2: Requested the whitepaper from IBM and it's literally just an 11 page marketing PowerPoint. Mentions blockchain a few times but doesn't explain how it solves anything that a normal RDBMS (or even some fancy distributed one with immutable records etc. where all parties are trusted) couldn't do.

Permissioned blockchains can be useful in trade finance and international trade. Financial transactions across borders can be delayed to allow for clearance and settlement between several institutions, which requires multiple banking systems to verify the integrity of transaction and collect a lot of paper trail. There are several competing projects solving for that problem right now.

I don't see why these would need a blockchain rather than just a centralized database.

I'm very skeptical of these use cases.

The purpose of blockchain is to solve what happens when neither side of a transaction trust the other.

For example, suppose US and Iran agreed to pay each other some amount as proof of their sactions deal...

US doesn't trust Iran or its central bank. Iran doesn't trust SWIFT, since it can be easily manipulated by its enemies (as it has been, before). US doesn't trust the alternative to SWIFT, since it is run by Russia and China.

EDIT: common people, that was just an example, it doesn't mean future transactions between US and Iran would be done that way. It was just an easy to understand example.

> The purpose of blockchain is to solve what happens when neither side of a transaction trust the other.

So what's the purpose of _private_ blockchains then? Grandparent comment was about "Permissioned blockchains can be useful..." not blockchain in general.

How does it remain private in a trustless case?

Alternatively, who keeps the blockchain private? Who manages access? If there is an impartial 3rd party, an "authority" or a "broker", a "governor" that all other parties can trust to do that, even if they don't trust each other ... can't that authority just use a database, with some checksums and signed rows if need be? What can't you get from a private github repo?

Is the "private blockchain" centralised or decentralised?

I feel that every time I see this discussion, the argument is shifted to a straw man whenever the wrong question is asked.

There's no purpose of private blockchains, unless your definition of blockchain is just chained signatures perhaps with a Merkle tree.

The intersection of the set of "private" and "mutually distrustful parties" is essentially 0.

That's what I thought, but I'd like to see a proponent of private blockchains explain it with out resorting to answering a different and more general question about "the purpose of blockchain is..."

OTOH:

https://apnews.com/article/fd4113419276444eba1d2a46d5c29752

In 2016, the US paid Iran $1.7B in pallets of EUR and CHF. The article's not explicit, but the settlement network probably uses a C-130.

Could you explain this example a bit more? US and Iran meet and discuss some deal? And then the want to pay each other some amount as proof of reaching the deal? Could they do it in public and invite various journalists to witness the post-signing conference where both parties say they have reached the deal? (It seems to be a standard procedure)

Or is the set of blockchain payments an guarantee of adherence to the deal? How would that help? Are the coins supposed to be returned in case of lack of adherence? If that is the case, how would I trust the other party to return the bitcoin?

Governments A and B meet and discuss some deal. Their agreement is recorded on a public append-only ledger, which is hosted by participants worldwide. If any party reneges on the deal, that's remembered by the public record too, where no amount of propaganda can erase it. Parties confirmed to be less trustworthy are subsequently afforded fewer compromises during negotiations.

A NFT could also be minted, where people and institutions stake money on the deal and if either party breaks the agreement, the NFT is burned. So stakers are incentivized to do whatever is within their reach to make governments stick to the deal - otherwise they would lose their investments.

The way to bootstrap participatory democracy in a world that only cares about the money is to bake it into the money.

What does renege on the deal really mean though? usually in those situations both sides will claim that the other is reneging on the deal

Engineering solutions based on binary ideas of true and false just don't apply to diplomacy or politics

Speaking as an engineer, that's what's wrong with diplomacy and politics!

EDIT: I define "reneging on the deal" as "acting as if the deal never happened".

The more governance decisions are recorded on the public record, the less opportunities there would be for parties to say "the other guy started it".

Also the deal could be set up to hurt both parties if they violate a predetermined condition. Maybe burn 5% of each party's GDP. Then they would be actually incentivized to collaborate.

> Governments A and B meet and discuss some deal. Their agreement is recorded on a public append-only ledger, which is hosted by participants worldwide. If any party reneges on the deal, that's remembered by the public record too, where no amount of propaganda can erase it.

You can do this with paper. Signed paper documents. You have invented the "treaty". It has been a thing for centuries.

A "signed paper document" or a "treaty" is also meaningless without robust enforcement mechanisms.... or the instant it's in either side's interest to ignore.

That goes double for blockchains.

The keyword here is consensus. Using an append-only distributed public ledger to record your governance decisions (and be held accountable for them) is a lot like using a memory-safe language when programming. It induces non-negligible overhead, but prevents entire classes of opportunities for abuse.

The whole "blockchain-backed international treaty" example is admittedly a bit contrived though. It's kind of a "horseless carriage" thing - trying to explain to @markwkw that no "blockchain payments" would be necessary, by expanding on their mental model. (Maybe that's an unwise strategy, and I need to start just rudely dismissing people instead, but I'm not sure how that would help with comprehension)

We actually already do this. See this job description: https://acpol2.army.mil/fasclass/search_fs/search_fs_output....

This would generally be responsible for paying parties that actually trust you, using Treasury checks and possibly small amounts of cash, but there is an equivalent position within the uniformed Finance Corps where you pay untrusted parties who also don't trust you. For that purpose, you deliver extremely large briefcases full of cash. Basically, the same idea as a drug deal where the buyer and seller don't trust each other. Everything is transacted in cash, and both parties are carrying a lot of guns. This is generally how we make payments to local warlords in theaters of combat where they are not by any means an internationally recognized legitimate authority you can make any kind of a treaty with, but you need to buy their cooperation anyway.

As for trusting they'll actually deliver what you're buying, again, that's what the guns are for.

Heck, as it stands right now just for normal consumers, buyers and sellers don't need to trust each other. They just need a legal authority who can prosecute each side and they need to trust that legal authority. Barring that, they need an extra legal authority they trust with guns.

As it stands, the obvious limitation of a blockchain is it only helps if your transaction is solely the exchange of data stored on the blockchain itself. Otherwise, you're back to the same issue. The fact that a transaction is recorded on a ledger doesn't mean either party actually received the goods they expected, and it doesn't mean they have any means of remediation, legal or otherwise, if they don't. The fact that a ledger says you own something doesn't mean you're in possession of it, and it doesn't mean the party that is in possession of it has to give it to you.

>The purpose of blockchain is to solve what happens when neither side of a transaction trust the other.

Normally the courts solve this problem, so this is only an issue if one or both parties are operating outside of the law.

Which, for normal financial enterprises trying to do business, creates regulatory problems: Chase can't exactly transact with the PLA without getting bulldozed by regulators, and you can't exactly hide the transaction on blockchain (since its immutable).

In the scenario you describe, there are ways of cheating even in blockchain (51% attack), and there are ways of solving the issue outside of blockchain (military force, embargos).

That's like the worst example ever. With international peace talks there usually is a trusted third party, like US was a part of various Israeli-Palestinian talks.

Banking systems are complex. You can't build a single centralized system that works for everyone, let alone get everyone to trust each other on the system. The solution needs to be decentralized, trustworthy and provide built-in checks for integrity.

Would you say that we have a "a single centralized system that works for everyone" in banking now? It seems more like a patchwork of a lot of systems to me.

No, we don't. That's why it's slow and expensive to trade across borders, especially if the counterparties have never done business before. It's an arduous process of proving creditworthiness through letters of credit. You often see document fraud where someone can tamper with a letter of credit, which is hard to detect.

> That's why it's slow and expensive to trade across borders, ... document fraud

Would you say that blockchains make this faster, cheaper and less prone to fraud?

Sure. Here is a story from 4 years ago. [1] Barclays says blockchain cut this process from 10 days to 4 hours.

[1] https://www.reuters.com/article/us-banks-barclays-blockchain...

I don't see a lot of news on that since 2016. Are they still using it?

Well, I'd rather provide a letter than put all my transactions in public eye.

It's not in the public eye. The blockchain is only accessible to trusted parties, like banks and merchant representatives.

Who manages access to the blockchain, and how do you trust them?

Yup. All of this is really about having a db for known counter party multi org db for financial institutions without having to basically fund new clearing corporations for each new market. Source: I was at Jpm on some of the relevant teams for a few years.

Docusign[1] has been using blockchain for a while now because it solves technical problems for their use cases.

[1] https://www.docusign.com/products/blockchain

Did Docusign really have a problem that couldn't be solved by any other means of publishing the hash?

Ultimately the hash comes from Docusign, so I'm not sure I can think of the problem case where someone doesn't trust Docusign to self publish that hash but does trust a hash that Docusign publishes to the blockchain.

Presumably, by publishing the hash on a public blockchain they are creating a trusted record of when the hash was published, which can be verified after the fact and which cannot be modified or removed, with planet-scale proof-of-work level of cryptographic assurance.

If they published the hashes on, say, their webpage or some third party's webpage, nothing would prevent them (or the third party) from redacting or removing the hash after the fact, given sufficient motivation.

RFC 3161 does the same, without a blockchain (public or private).

And how would you use RFC 3161 as a company that wants that use case?

I'd argue a more popular blockchain than their in-house one would provide stronger proof.

For example, a Bitcoin one: https://www.proofofexistence.com/

It looks like that is using 0.00025 BTC per transaction, which currently is $12 USD, that seems quite steep for a single document verification.

it is about timestamping basically nothing else. basically that cannot sign something in the past. Though you can do the same with sequence number, and publicly publishing all signed hashes.

Or cryptographically sign a statement with a timestamp.

Parties can prove things without others needing to trust anyone.

You can put information on the blockchain and others can be sure it can’t be removed.

There are use cases.

> Parties can prove things without others needing to trust anyone.

Yes, but the only things you can prove without trust are events that happen 100% inside the blockchain. Which, AFAICT the only use for a system that works that way that I've seen is cryptocurrency. The other one people were really hot on was supply chain, but, from what I understand, when you have supply chain trust issues, they don't look like "oh gee someone edited a database record", they look more like https://www.bloomberg.com/news/articles/2021-03-09/trader-bu...

Which, ironically, that's not a great use case for cryptocurrency either. Traditional escrow services are a better fit. If the trader had bought that tanker full of rocks with BTC, there would have been no way to reverse the transaction after it had been determined to be fraudulent.

So, yeah, blockchain is mathematically provable to have certain properties. But, like with any proof, those properties only hold for as long as the proof's assumptions hold. And it's really, really difficult for us laypeople to recognize when the assumptions do or do not hold when they're defined in terms of technical jargon that uses a familiar term like "trust" but assigns it a subtly but critically different definition from the everyday meaning.

You’re describing a number of limitations, some of them more valid than others.

I don’t think blockchain is worth the hype it got a few years ago, but still, with these limitations, there are use cases. That doesn’t change because you say ‘this use case doesn’t work’.

>but, from what I understand, when you have supply chain trust issues, they don't look like "oh gee someone edited a database record", they look more like https://www.bloomberg.com/news/articles/2021-03-09/trader-bu...

>Normally, in such cases of non-delivery a trading house could make a claim against a cargo’s insurance policy. But Mercuria found that just one out of seven contracts used by the Turkish company to insure the cargo was real. The rest had been forged.

Can't forge a smart contract.

Fair, though that would be a much more compelling observation if anyone had ever succeeded in implementing a full-fledged insurance policy in the form of a smart contract.

I'm curious, for example, how you'd get an errors and omissions clause working in Etherium. Like, how would Ether arbitrate a claim against that policy? Assume, for the sake of argument, that hard AI has not been invented yet.

You're correct that hard AI would be necessary for the blockchain to perform autonomous arbitration in cases where human discretion is necessary.

In practice, this is solved by giving the contract the capability to query an external system (referred to as an oracle), which provides the results of the independent arbitration as an input to the contract.

Thing is, "without trusting anyone" isn't that relevant most times. The entire system of property rights is based on trusted notaries. Works as well as anything.

It doesn’t work internationally, but we’re used to that because there never was an alternative.

> Works as well as anything.

Which is to say, just barely well enough to keep going.

And then there's the whole thing with how its scaling issues are mitigated via the platform dependency on the state's monopoly on violent enforcement. Emphasis on monopoly.

So the big problem in your opinion, is that we're not allowed to legally beat each other up like animals over property disputes.

All right.

By the way, I don't think blockchains allow you to beat up people, either.

The big problem, in my opinion, is that a lot of people think we'd inevitably be beating each other up like animals, if it wasn't for the powers that be, who kindly protect us from ourselves.

And it is already legal to beat up and kill each other over a property dispute. It just has to be a large enough dispute for the parties involved to be able to afford rebranding it as a "war".

Do you know this saying "those who don't know their history are doomed to repeat it". You're that saying.

Also "war" is the thing that happens between parties above which no legal frame or enforcement institution exists. Countries. There's no actual "international court" (there's the UN one, but it has no powers). This is why wars happen. So in fact, mentioning wars defeats your own point - yes, people will literally kill each other like savages when no legal repercussions exist. Wars show that.

Because we have no world government, we can only apply mitigation strategies like sanctions, diplomacy, economic interdependence. These work, but only until a true scarcity occurs, where taking someone else's stuff is a solution. Then it's back to wars.

To add, it's also completely legal for the powers that be to treat you like an animal if you try to make yourself independent of them.

Unlike the existing system of governance, a blockchain doesn't have the mandate to beat up people.

I prefer a subset of people who can beat me up for a subset of reasons, rather than all people for any reason.

Your boot, sir.