I have not seen any clear explanation of how these networks of interacting contracts will be verified, so you know they will work the way you intend. Anyone with any knowledge of the formal verification of software written in Turing-complete languages knows that it is difficult, and it is something that not even many programmers know how to do. Until I see a plausible answer to this question, I have to regard the sort of future presented here as a flight of fantasy.
What is Ethereum?
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Re: What is Ethereum?
#32Bitcoin transactions are scripts that execute sequentially and are very restrictive. Ethereum instead took bitcoin and replaced that scripting language with a turing-complete language.
Now, consider the conditional operator in the given example.
"If a transaction occurs.." is the condition. ONLY the conditional of transaction types can be verified by the program because it is inherent in the network. For every other conditional, for example, "if team A wins.." the program has to consult a third-party. These are known as 'oracles' in ethereum lingo.
Now since we are trusting a third-party, why can't we simply use bitcoin and even let the decision script be hosted on the third party?
For the program to be able to take decision on a real-life event, only the occurring of a transaction is the type of event it does not need a third-party for. And trusting is all the problem there is.
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Bitcoin's script not being turing-complete is a feature because it specializes the use-case. Theoretically, if ethereum allows a turing-complete language to be executed, a code could be written to hack the system itself. Ethereum handles this by executing in a virtual environment.
Thus ethereum is essentially a abstraction on bitcoin and introduction of a new currency token (ether) is unnecessary.
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The vision of ethereum is very desirable. Although Ethereum does not make it possible I want such a system to exist. My limited understanding is that for a system to exist, we need an algorithm to be able exchange private keys between two parties without trusting each other.
We need a homomorphic secret sharing but without a dealer. In a Blakley scheme, both parties chose their own planes; we need the intersection of planes, the line, to be our private key and for everyone to be able to know the public key for the same without the private key being known to anyone.
Does anyone know of such an algorithm, because solving this problem will also truly decentralise cryptocurrencies like email.
Re: What is Ethereum?
#33This is a terrible description of Ethereum and trivializes what it is. The interesting parts of a contract are not the deadline and the transfer of funds. Even an escrow service can provide those functions. The interesting parts of the contract are the conditions of the transfer of funds, and how those are evaluated prior to effectuating the transfer, and how the obligations are enforced after the transfer. What make…
I agree, I think the website is failing because it doesn't touch on a key topic, one that you mention: How does Ethereum handle non-blockchain items?
It's easy to see how a blockchain might handle money payments (using its own money system, that is), but far less clear how you can encode contracts for real-world items. Like the example website, for instance. Just because a blockchain entry states 'x' doesn't give it any legal weight, and certainly doesn't transfer real world possessions or ownership.
As you mention, one of the key features is verifiers. Say I am selling a website. We need to ensure that the money transfer happens only once I have control of the site. (and presumably, that the site has been built and is complete). We need a trusted party to check that this is so, and the ethereum contract needs to have this verifier written in to it.
Re: What is Ethereum?
#34In the samples there is an unbreakable marriage contract where divorce is only possible if both parties agree. Scary.
Re: What is Ethereum?
#35So it's a currency, a contract system, a new form of law, a distributed computing system... I think I need to lie down. These explainers I keep reading are not helping. Can anyone tell me whether this is some giant boondoggle circlejerk, or something that is really going to be used widely and perhaps lead to things changing?
Is this going to be widely used? No. It's early technology.
Will a successor of this idea change things? Yes.
Re: What is Ethereum?
#36The example contract is very vague and seemingly pointless. The stated problem is 'if the buyer pays before 1st April, then they own the website'. Fair enough, but usually you'd just deal with this without any kind of contract in place. We don't need contracts for simple cases of 'buyer pays money, gets purchase.' A contract would only be interesting in the example if it was structured as an option: The buyer has pro…
The data for WEBSITE_ADMIN is set inside the Ethereum network. I think the term 'website' is tripping people up here. It's actually better defined as 'site with data' which can be accessed via the Ethereum APIs. If you are interested in playing around with the API calls, there is a Docker image for it. I put together a hosted version of this as well, so you don't have install anything to play with it: https://github.com/giantswarm/swarm-ethereum
Re: What is Ethereum?
#37Presumably smart contracts would very often depend on input external to the system - for example, imagine a will that says if Person A dies, Person B inherits the millions of dollars worth of Ether at a particular address that Person A owns. Somebody (or some other system) has to be in charge of the input to the Ethereum system to tell it that Person A has died. This seems like a huge single point of failure that doe…
While I generally agree with your point, it seems to me like that specific scenario could be solved with a dead man's switch contract. Not ideal, but still better than other cases.
I got the impression that the answer you'd get from the Ethereum team is: at the worst case, this is just as bad/good as the current system - i.e. real world effects have to be mediated by an executing authority, same as a real world contract. They would add (and I agree) that smart contracts still have advantages, even in this case.
Re: What is Ethereum?
#38What is really interesting is when parties sue each other in court over Ethereum contracts. Courts will always be involved.
Re: What is Ethereum?
#39Isn't fuzziness a feature of most legal codes? Treating the law like an absolute immutable contract sounds anathema to a healthy judicial system.
I'm not sure why some technologists have such a fascination with legalism.
I'm not against the idea of digital government and having laws be distributed under a free documentation license with the ability for citizens to discuss and amend laws. A standard version control and issue tracker model sounds much more appropriate, however. Perhaps even just email and diffs, so as to have a barrier to entry.
Re: What is Ethereum?
#40Bitcoin transactions are scripts that execute sequentially and are very restrictive. Ethereum instead took bitcoin and replaced that scripting language with a turing-complete language. Now, consider the conditional operator in the given example. "If a transaction occurs.." is the condition. ONLY the conditional of transaction types can be verified by the program because it is inherent in the network. For every other…
Yes, the problem is about not what happens on one machine, but N machines globally. That is a system that scales linearly and does not use proof-of-work. One needs to solve the Byzantine General Problem in a more general way than Bitcoin does.