Could you give a high-level explanation of what's an offline-first blockchain here, and what's the difference between TrustChain and Bitcoin ? The draft seems very low-level and complex to read, and the article contains very few technical information.
Trustchain is a ledger which is consensus-free. Forget anything you know about chains and ledgers.
By using legally valid digital signatures it is possible to sign agreements which are irrefutable. If you have two parties which sign a contract, it become legally enforceable. Trustchain requires that any block is signed by multiple parties and thus become legally enforceable. Every transaction forms its own "micro-block". Mono-signature transactions are strictly not allowed (e.g. Bitcoin,Ethereum approach). Once signatures are added to a block its valid: instant finality. Weird...
Edit: no native token or money creation. Its just fabric for recording transaction micro-blocks. Non-profit. So nothing like Bitcoin at all. So works very well with dApps, Distributed Apps, no smart contracts needed. Scientific publication about Euros, DAO, dApps, passport-grade identity deployment: https://dl.acm.org/doi/abs/10.1145/3428662.3429744
So is there a reason to call it “blockchain” except for marketing reasons?
(I'm currently working on a Paxos-based distributed system for an industrial application, and my client insist in calling that a “blockchain” in all internal communication because, you know “blockchain” sounds cool to them)
Distributed ledger would be a better fit indeed. However, nobody then understands what it is.
It offers tamper-proof micro-blocks, distributed validation, and leaderless governance. So this is more then idle marketing. But you're right, the name "Trustchain" is specifically tailored that government leaders and managers feel trustworthy and cool about it.
And how could it be if it works offline. If I have a phone in some state s. Then I can just do the transaction and revert the phone's state back to s and spend the money again.
Correct. The double spending is not solved technically, but critically relies on a functioning legal system.
Every time you create Euros, you simply create a negative balance. If you offline sign multiple I Owe You contracts, you accumulate debt. Just like in the real world, if you sell your house to 12 different banks, you have a (felony-level) problem.
We ensure that double spending is detected with certain guarantees. Each micro-block with a transaction within Trustchain needs to be signed by two parties, so each copy is valid. Block hiding attacks wont work then.
The proof-of-work system is very elegant. The emergent properties of mining have created an amazing ecosystem. But slow finality might be a showstopper for mass uptake. Our alternative with instant finality using multiple legally binding signatures might offer a way out.
Yes, you need something against tampering. However, once you legally signed something, the contract/transaction is valid.
Various mechanism can be used to ensure integrity. What we implemented specifically is that various witnesses can inspect your Trustchain blocks and co-sign your balance. So any node can act as a digital notary. You can also use a reputation or trust function.
Here is a master thesis from Mathematics on distributed accounting systems. It contains numerous new mathematical proofs around integrity without strong identity assumption; .PDF "On the Sybil-Proofness of Accounting Mechanisms in P2P Networks", https://repository.tudelft.nl/islandora/object/uuid:6b4011c6...
I've dreamed of something like this too. I think it fills a good spot especially smaller transactions.
I see parallels to the nordics bankid+swish, bank issued id/phone payment system. It's flawless in execution but both the id(!) and the payment part carries a cost picked up by the person accepting money (about $0.12 for each, very bank like). With your way of doing things none of the parts has to cost anything at the reasonable expense of potential double spending.
Second, if multiple parties are involved (I have to assume you mean more than just the needed 2 parties), wouldn't that mean you must be connected to a wider internet?
UK minister of Digital infrastructure only some weeks ago announce their vision, far away from running code and new laws [1]. Dutch secretary-of-state on same days also send his digital ID vision to parliament [2].
I'm Spaniard. My national ID has a chip and I use it daily to sign documents with a card reader and a password. You can change your password at police stations that issue ID cards. The signature is legally valid.
Could you elaborate on double-spend protection a little? I skimmed the protocol draft and came away with the impression that the goal is not so much to prevent double spending directly as it is to flag users who do attempt it, so future payees know to refuse to do business with them. Did I understand correctly?
Exactly. Using protocols to prevent double spending hurts performance and scalability. Detect fraudsters and ignoring them is cheap.
This is a fundamental issue I believe. If you have a stable legal ecosystem you can use the law of the land to ensure that double spending has real-world consequences. Preventing double spending is expensive. Guaranteed double spending _detection_ might also be sufficient and scales horizontally.
The "your papers please" argument. It's true. If you live in a world where you are compelled to present an identity for any financial transaction, then there is no need for bitcoin, to prevent double spending.
This requires permanent identities, right? So compared to cash payments, this system is potentially more oppressive because you can be rendered unable to pay for things.
I imagine there are some sticky legal questions to solve there - usually this kind of intervention in a person's life would require a court order or similar.
How traceable are transactions to the payer? Is there any anonymity?
Ignoring fraudsters will only work if that causes a cost to the fraudster bigger than the gain by double spending. Basically you will have to use key pairs tied to natural persons. If there is any anonymity or pseudonymity the fraudster will just generate a new key pair and double spend again. How does this system guard against that ?
we are building upon our own lightweight, scalable distributed ledger which has been in development for many years now. This ledger is based on the swift detection of double-spend behavior. You can find details on the fraud detection algorithm in our peer-reviewed paper, see https://dicg2020.github.io/papers/devos.pdf (an extended version is currently under review).
We have also performed scalability experiments on our nation-wide compute cluster to estimate the throughput of our distributed ledger. These experiments hint that our ledger is easily capable of handling 100.000+ transactions/sec.
> The customer scans the code, sees the amount to be debited, and presses OK. The amount then moves from one phone to another without the need for WiFi or another wireless network
How does the business verify a transaction was successful? It seems like information only flows one way.
Is there a specific reason there are only Android apps in the repository? Is there a restriction in iOS that makes this app not portable, or were researchers only known with the Android ecosystem?
Its different mostly in the methodology and requirements.
GNU Taller is developed without input by governments or existing legal frameworks. Christian Grothoff has done pioneering work for years. Its ideology driven, not government driven.
We're different. We are trying to ensure compliance with very complex eIDAS regulations, GDPR, KYC, and AML. In partnership with governments and Brussels are trying to discover what is possible and desired.
How is this linked to an iban account. Is it a bit like a one off sepa? I've always been curious as to why iban is not used more, say I don't care for credit cards and just want to trust my customers.
Well, IBAN is just universal account number. The actual transfer systems are more complex and differ heavily between EU countries.
You have SWIFT, which is general correspondence-based system for international transfers, of which SEPA is essentially a special agreement on how certain setup of SWIFT transfers are to be handled (essentially if you select certain transfer parameters you fall under agreement rules, otherwise not).
Intra-country transfer systems have more variability, unfortunately I can only speak about how UK and Poland did it, with UK having a very legacy numbering scheme where you only touch IBAN when you do international transfers (at least when I dealt with it last time in 2014), whereas in Poland all banking uses IBAN accounts (minus PL prefix) because that's what national interbank clearing system uses - and by extension paying for things by bank transfer are the norm, with widespread usage of the large "address space" of IBAN to create individual accounts even per contract (for example, if you take a loan, or pay for some service, you will usually pay to a bank account made just for that contract).
Ultimately, the difference is that there's effectively no extra cost for handling bank transfers in Poland, the clearing happens fast enough (usually max 1 business day, there are multiple clearing batches per day and it essentially depends on whether your transfer enters the system before the last batch of the day is calculated - with UK, I encountered multi-day wait times). Since there are no cheques, you essentially have three options - cash, bank transfers, and cards - and accepting bank transfers is the simplest approach outside of "cash direct in hand". An ecosystem of utilities to make it even simpler had grown out of making common simple & fast way of doing electronic transfers.
with Faster Payments local transfers in the UK happen instantaneously. this has been the case for more than a decade. all banks participate and makes transferring funds in the UK a breeze.
to give you an example as to how fast this payment system is: i press pay and the money is received on the other end before the “successful transfer” screen pops-up on my device :)
for international payments i’ve noticed that it takes less time to receive money from the UK than it is for the receiving party to do a local transfer :)
It's distribution was very unequal in my experience (2008-2014). Not as bad as USA, but still. And of course the acceptance of bank transfers seemed hilariously low vs cheques.
That is a lengthy story.. We basically forked the Tor protocol and decentralised it. This makes it Bittorrent friendly, offer end-2-end crypto, and would scale to Internet-wide usage. We're planning to port our deployed Python Tor-stack towards Kotlin for the Superapp and Trustchain.
That is the golden question. How anonymous will the upcoming digital Euro be?
Politicians and European Central Bank will decide on this soon. Delft University has tested out technology which could offer equal privacy as cash money. Will this be legal?
First, I'm happy to finally see a blockchain project that isn't accompanied by its own token, and therefore isn't pursuing a quick cash grab, nor incentivizes gambling.
Second, what do you tell your friends and family who ask if they should buy bitcoin? As a former owner, I've become ridiculously wary due to the shady individuals behind it. If the price is propped up with shady fiat money and imaginary exchange tokens, what guarantees that the bitcoin price reflects the true supply and demand?
> Second, what do you tell your friends and family who ask if they should buy bitcoin?
I say "go ahead but don't put more than 5% of your portfolio on it, preferably 1% or less". Also, I'd recommend buying a crypto index fund instead of BTC directly.
Personally, I'm long term bearish. But the last decade has shown that "long term" may be reaaaaally long.
Central banks in many countries (including all of Europe, US, Canada, Japan, etc) are all effectively in public hands.
The banks' boards and many employees are political appointees nominated by elected officials.
They are accountable to legislatures.
I'm not sure how, other than go for a "Swiss-style" direct election of directors (which, considering the complexities of macroeconomics, would be like shooting ourselves in the foot with a cannon), you could get more public than that.
For example, if I run a business which banks do not approve of, then they can block my account or make it impossible to make transfers. What good does it if the bank is "in public hands" in that case?
As far as I can tell, this is programmable money backed by legal digital signatures.
For the first time since the whole blockchain hypetrain started I am actually interested in this.
The Netherlands doesn't 'need' cryptocurrencies, as our banking system already works very well. We can already easily transfer money for free using a mobile phone (apps known as 'Tikkie', and 'betaalverzoek'). We have a secure and instant online payment system (called 'iDEAL') since 2006, which works very well. We also have some pretty decent ways to do digital signatures (called 'DigiD' and 'e-Herkenning'). I believe that any blockchain tech would be a step back when it comes to cost, insurance and end-user convenience.
Seeing an alternative payment system that is programmable seems refreshing to me. I just wished they didn't use the word 'blockchain' in their marketing lingo.
So, i have an old phone, i put 100 euro on it, then put it in flightmode, and make a backup. Then i start paying stuff, and when the 100 is finished, i put the backup back. I know the double spend is not solved with this paper, but how does the retailer know this is a phone from a double spender? He shows a QR code to the customer, and not visa versa. The retailer does not know anything from this customer.
Currently the only route is to: request permission from a Central Bank in Eurozone, download the Gateway code, and finally issue your own coins. (we got approval from our central bank)
> He emphasises that money transfers are an essential infrastructure that belongs in public hands. As far as he is concerned, De Nederlandse Bank (DNB, the Dutch Central Bank) is the appropriate body to bring the digital euro into circulation after the physical euro becomes redundant.
Note this is not a normal blockchain: its an offline-first blockchain [1]. Open source [2].
[1] https://tools.ietf.org/id/draft-pouwelse-trustchain-01.html [2] https://github.com/Tribler/trustchain-superapp