Ethereum, Bitcoin’s most ambitious successor
america.aljazeera.com
america.aljazeera.com
Turing complete contracts add a whole new level of complexity (e.g. http://en.wikipedia.org/wiki/Halting_problem). I guess many (most?) could be solved by limiting computation time - it it's still a scary world. If one just considers how many significant issues the much more basic Bitcoin protocol has managed to hide (e.g. transaction malleability). If implementing a "basic" protocol is that hard - the idea of a turing complete protocol is formidable!
The halting problem is not a practical issue with Ethereum, because the system doesn't care, in advance, whether or not a contract will halt. It will just run it to find out.
Nodes can't be compensated for this— only the single miner who chose to burden the chain with the contract. Everyone else has to go along for the ride (or skip verifying it and hope that the anonymous miner wasn't lying). This is one of the reasons Bitcoin has very purposefully eschewed contracts which are computationally expensive to execute.
You can almost always perform a computationally expensive contract externally to the system and bind it with a hashlock or multisig, in any case. The inability of the a consensus system to perform IO to outside world usually demands those techniques in any case.
Imagine someone develops a chip that can calculate ECDSA operations 10 times faster, consuming 100 times less electricity. In a well-functioning market, the consequence of this would be that the price of ECDSA operations would drop, to reflect the fact that they now cost less to verify. With fixed fees, this isn't possible, and there is no financial incentive to optimize any given operation, without optimizing all operations simultaneously.
Such a network can grow to some extent, but how can it truly scale? There is limited scaling, of course, but node requirements increase as traffic increases, and there is no scalability through distribution of computational resources. So the more work the system does, the stronger each node needs to be.
If the answer to this is, "No problem - we'll just make it more expensive," then the required computational resources could be purchased with the very cryptocurrency that is generated from the system. At that point, it seems to me that the snake eats its own tail.
Regardless, before we declare that there can be any democratization enabled by this tech, I think we need to ask the question, "How does this not transfer even more power to those with the most computational power?"
Put another way, it seems this is tailor-made for Google and Amazon, not an organization of Joe Publics, each with a couple extra GPU's installed. It's still going to be about the "haves" and the "have-nots."
I'm happy to be proven wrong on any of these thoughts. I just think that if we were talking about any other tech, this computational model would not be considered scalable in any meaningful way.
Now try calling some lawyers and ask them how much it typicaly costs to defend a contract in our traditional court system... it will probably be a number 100000% higher than 50 cents.
Cryptocontracts are great for Joe Publics.
From there you can write contracts that do things similar to their paper, real-world counterparts. Say you wanted to set up a one-year rental contract. The landlord would create the contract and you, the tenant, would transfer your security deposit into it. The contract would have logic something like this whenever it is activated:
if rent money was just deposited
transfer the money to the landlord
mark last month as paid
else if payment is more than 30 days overdue
transfer security deposit to landlord
end contract
else if one year has elapsed since contract started
transfer security deposit to tenant
end contract
The idea is that instead of a contract being enforced by the good will of the participants, or a court if that fails, it's enforced by the logic programmed into the contract itself.
This ignores the reason for a deposit in the first place. What if the carpets were burned in that year? Some of the deposit needs to be kept by the landlord. How does etherium know the carpet was burned? If the landlord says so, then the landlord may be lying.
For simpler operation - if rent not paid - then end contract - that sounds like it adds no benefit. No need for a program to tell you the contract has ended.
This is very useful to prove authenticity of a contract and for very simple contracts as well such as a bet. If there can be any sort of dispute about the contract though I don't see how it can be useful again save for authenticity.
https://github.com/ethereum/wiki/wiki/Whitepaper-2-Draft#com...
I basically just chose to keep it in there because it makes a few contract types easier.
(def (collatz-depth x)
(if (= x 1)
0
(if (= (mod x 2) 0)
(+ 1 (collatz-depth (/ x 2)))
(+ 1 (collatz-depth (+ 1 (* x 3)))))))
However, it's not magic: it's not automatically trivial to generate such a proof of termination (I'd assume there exist definitely terminating programs for any given proof system that cannot be proven to terminate in that formalism), and it may be a moot point since a slow enough algorithm is for all intents and purposes non-terminating...
I don't understand how is that relevant. Why is press so sexiest these days? Are they trying to toehold to anything even remotely political to get the views?
For me is like they have said, a team mostly based on <random city>
If the team was based in San Fransisco, it would be part of the established silicon valley culture, versus if it was based in an emerging tech hub, then the story would be that they are part of an emerging tech hub.
Very little can be written in journalism that isn't relevant in some way.
However, note that every frontier field is male-skewed, probably due to lower male risk-aversion. So this philosophy is anti-innovation.
Swiss Law might be a bit idiosyncratic but I would hardly call it a "legal free-for-all".
The general four categories of options that we had are:
(i) a traditional banking/tax haven (Isle of Man, Panama, etc)
(ii) Switzerland
(iii) Iceland
(iv) Singapore / some other "Asian tiger"
The reason we discarded (i), aside from reputational concerns, is that such jurisdictions tend to be unstable; they are nice to you right up until the US government wants them to stop being nice to you, at which point they flop over in ten seconds. (iii), while nice for other crypto-startups, is bad here because there is unfortunately a hostile legal environment for cryptocurrency. The choice between (ii) and (iv) is arbitrary; both categories of jurisdictions have a good legal environment for these kinds of projects, and both have a reputation for being reliable and consistent. We chose Switzerland because (1) the government is more accessible, so there is no need to wait six months to talk to regulators, (2) we are working with OpenTransactions, who had an established understanding of the local legal environment and have been able to provide massive help to us, and (3) because it's linguistically and culturally easier for us to deal with Swiss regulators than Chinese regulators.
So it's not at all a free-for-all; it's a solid legal environment with an established reputation for stability that meets our objectives. If we wanted/needed a true free-for-all, we would be working with Panama.
I can see why Switzerland is a smart choice, for reasons such as those you give.
Basically it's an article on an interesting topic. I just wish a better source had been posted.
And it is disabled on most clients to avoid trolling and DoS attacks.
EDIT: It is addressed on the white paper: https://github.com/ethereum/wiki/wiki/%5BEnglish%5D-White-Pa...
This is a common misconception. Stock nodes won't relay transactions with weird scripts by default, but they're perfectly valid in the blockchain and verified by all nodes once someone configured to mine them has mined them.
> It is also not Turing-complete
Nor, pedantically, is what etherum proposes. Nothing time and space limited is.
What consensus systems like Bitcoin (and alt coins) do, however, is not executing programs in so much as that they are verifying an execution transcript that someone else performed (which is why all nodes compute the same values). Verification of an transcript of even arbitrary program execution is in P— you don't technically need turing completeness to express it. Though some forms of transcript expression may be more efficient. What Bitcoin does has the advantage of making the computationally work simply statically decidable— it's proportional to script size— and this relation means that— within reason— there is only one limited resource transactions have to worry about consuming, which makes the appropriate fee model obvious.
It would be like if the entire web split into mutually incompatible partitions the first time someone crafted some JS code which behaved differently in IE and Firefox.
This is not correct. It's a part of the consensus system rules and cannot be just enabled and disabled on a node by node basis. It must be preformed precisely and identically on all systems.
What is the case is that nodes don't relay transactions with unusual scripts to prevent DOS attacks, but once they're in a block they're fine.
Anything that is completely people-operated is a certainly oppressive system.
Lately I have become much more comfortable with the idea of computer-controlled systems for one simple reason: our world is already computer controlled. The computer in question is the universe with its laws of physics and humans provide the inputs to this great multisig by manipulating their body parts. At the "base layer", no semblance of compassion really exists: the person who wins is the one who can wield the most violence. This is true even in anarchies; when it comes down to it, it's the guy with the guns who has the final say. And yet humans have managed to take this base layer and build all sorts of other structures on top. The world of programmatic smart contracts is exactly the same; it's just a set of cryptographic "laws of physics" that you can build stuff on, except it's designed to be both much more efficient and at the same time voluntarist at the core - unlike in the "real world", it's much harder to successfully steal a private key than it is to create and use one.
A an impartial system of rules may not be understanding of specific emotional contexts, but it is by definition fair. This is because it will always behave in the same manner given the same inputs.
Given the judicial reality of most present (and past) societies, I would trust my fate to a carefully designed legal algorithm over a human jury every time.
https://www.youtube.com/watch?feature=player_embedded&v=jjzz...