Just Enough Bitcoin for Ethereum
medium.com
medium.com
Every time I read a "Getting started with Ethereum" guide which involves 7 steps just to buy Bitcoin (from a site nobody's heard of) and then set up a wallet, I watch the number of potential users dropping like a rock.
I hope very much that it succeeds enough to justify its learning curve, as it's an interesting idea. But I suspect that outside of a few very small markets where it offers the ability to do something completely impossible with any other method, having an ethereum interface for your product or service will be roughly equivalent to GPG signing all your emails: People in the know weren't that concerned anyways, and nobody else knows enough to care.
[0]: https://metamask.io/
Give it time. Or better yet, help us! This technology is about to reshape the world.
It's a shame that it's not default on Windows or Android yet, but it unfortunately makes sense since they have to run on so many different configurations (unlike Apple which can ensure that everything running their OS' are capable of full disk encryption without a noticable performance hit).
I know it sounds like marketing but it does remind me of the early days of the web, like 95, before the web was serious business. It's all toys and gizmos, the hacker equivalents to water ripple effects, with frameworks coming in to help people build more interesting and production-quality things.
Very basic questions persist such as how to best store large data files (ipfs looking like the clear winner), how to reference them, how to design a currency, how to avoid designs that are too stiff or get stuck in a state where they can't be easily updated, how to express an application model in smart contract form, how to best represent a user account, etc. If that sounds fun, jump in, if you were wanting something that matched the hype, wait a few months. Apps on Ethereum can be as expressive and polished as the apps you use today, and can even be designed just as centralized as the apps you use today, but with properties you would typically think of only belonging to Bitcoin.
How are things going as far as tech, adoption, etc for Ethereum for those in the know?
The source code for the contract can be made to have a proof of correctness in it, or, as it is probably not all that long, if you look at the source code long enough you can be sufficiently convinced that it runs how you expect it to.
Regarding the problems with turing completeness, any transaction is guaranteed to finish within a particular number of steps, because the transaction includes an amount of "gas", which puts a limit to how many steps the contract will run. If it runs out of gas before finishing, all the changes in the state are reverted (but the person still pays the gas cost). If it finishes, then the extra "gas" is returned. (the transaction specifies some "gas cost", which is how much ether per gas or gas per ether (idr) , and some amount of ether, which is the max cost the transaction is allowed to take. There aren't "gas balances", any "gas" that is transferred just is ether at the end. Its just a unit of how much computation, and the gas price is how much they are willing to pay per amount of computation. I feel like I didn't explain this well...)
Checking that the contracts were run correctly is done by anyone verifying the block which contains the contract call. If the miner runs the contract incorrectly, then the people verifying the block will not accept the block as valid, so people won't mine on the block, so it wont end up in the main chain, so the miner will not receive anything from mining the block, and what happens in the wrong execution wont effect anything.
I'm not sure if this explanation has been very clear, but I hope it has been clear enough. I can try again if it isn't though.
>The source code for the contract can be made to have a proof of correctness in it..
Has this capability already been implemented for the Ethereum contract language(s)? If so, I would greatly appreciate a link, as my admittedly cursory search did not find it (there is some discussion of verification of the Ethereum infrastructure, but that is merely a precondition to contract verification.)
Even so, I think it is significant that only a tiny fraction of today's software is written this way, and only a tiny fraction of all developers know how to do it. Someone has to write these contracts.
>... or, as it is probably not all that long...
Ethereum's promoters are imagining nothing less than a revolutionary new economy, with vast networks of interacting contracts. The amount of contract software implicit in these dreams is huge.
>If you look at the source code long enough you can be sufficiently convinced that it runs how you expect it to.
The steady stream of security vulnerabilities that are being found in ordinary software shows that this is not an effective technique. If you are a software developer, imagine doing your work in an environment where any bug of yours could cause you, personally, to lose a significant amount of money.
Nor do I think 'gas' completely solves this problem. Now your analysis has to cover the issue of whether your contract, or any of those it is dependent on, will run out of gas before completion. In most cases, and particularly in networks of dependent transactions, reverting back to the initial state is not a viable outcome (imagine that happening on the last payment of your mortgage on a house.) I can imagine that running out of gas on some obscure corner case might be used by an attacker as as a means to disrupt a network of dependent transactions.
It is planned though.
Ok, yes, I suppose that the contracts will/would eventually get kind of long. As it is now though, It hasn't taken me /all/ that long to read the contracts I've looked at. (But perhaps I've only bothered to look at the ones short enough to read )
Regarding finding security flaws despite people looking carefully: yes, that seems a good point. I think proofs of correctness will be important for important contracts. However, many contracts logic is not really all that complicated. A contract can be powerful without being complicated, I think. Because of this, I think much of the time the proofs should not be too hard to write.
Regarding running out of gas:
Well, yes, if the transaction you send does not have enough gas, and you needed it to run, that could be a problem. But, if you run the transaction locally, and use that to estimate the amount of gas which needs to be used (might not be exact if the state of the contract changes in a way that your transaction needs more computation, but for reasonable contracts I think this would not be much), and one can provide extra gas in case this happens (the extra gas will be refunded), to have a high confidence that it will be enough.
But, if the transaction is important, one would be watching what happened carefully anyway, to make sure the transaction gets in the chain, regardless of the complications from the computations in the transaction. If, counter to your expectations, the gas you provided did not end up being enough, then you would be able to notice this, and, though you would be out that gas cost, you could just send the transaction again with more gas.
The block times are very short (under a minute), so you probably wouldn't have to wait long to send the transaction again with more gas. Most of the gas costs shouldn't be too large, so unless the transaction you are sending is very time sensitive, or very computationally expensive, a transaction running out of gas shouldn't be /too/ much of a problem?
I think you make some good points btw, just explaining my understanding of how those things are addressed.
Also, I'm not sure, but it seems you might have a small confusion about gas. Gas is included in the transaction, not stored by a contract over time. Gas only exists within the context of a particular transaction, the token which is actually exchanged is ether. You might have just been choosing not to mention the details of that though.
Why is it the problem? Because contract with something like while(1){}; will render the entire network of nodes useless.
An example may be useful. Suppose I tell you that I have written an Ethereum contract whereby people can loan me money, and after a year, I will pay them back double. Before you enter into one such contract with me, I hope it would cross your mind to wonder if I might actually be running a Ponzi scheme. Don't worry, I say, Ethereum has this gas feature that means the transaction will always halt. How much more confident should that information make you feel?
As for your alternatives, gas is essentially the same as limiting the time of computation. If backwards jumps were disallowed, the language would not be even approximately Turing-equivalent.
2. There are Turing-complete languages which only allow loops with known number of iterations.
3. Check my presentation, If you want to understand Ethereum programming model:
http://www.slideshare.net/mobile/nivertech/ethereum-vm-and-d...
IMO Ethereum is just a first step in the right direction, the real solution will need to be much more scalable.
I am not sure why you are mentioning this here, but if this is what you think I am misunderstanding about gas, perhaps you could point out where you think I made this mistake.
>2. There are Turing-complete languages which only allow loops with known number of iterations.
You did not originally write "loops with known number of iterations", you wrote "disallowing jumps backwards / loops".
> 3. Check my presentation, If you want to understand Ethereum programming model.
Based on your contributions to this thread so far, I am not very confident that I will find my specific question addressed, but if you give me a specific slide number to start at, I will give it a look.
BTW, do you have an answer to the question I posed in the second paragraph of my previous post?
Again, it has nothing to do with gas. You just need to review/audit the contract's source and EVM code and be sure it doesn't have backdoors.
For simplicity, you can think about Ethereum Transaction as an RPC call to Ethereum contract, where in addition to arguments (Data), you can also transfer a monetary value (in Ether) and provide fuel (Gas) for contract execution. Gas price (in Ethers) serves the same function as Bitcoin Tx fee.
Gas mechanism is just an implementation detail.
EDIT:
Regarding the contract example you mentioned "unsecured loan", I'm not sure it can be implemented as a "Self-enforcing contract", which is a proper term for "Smart Contracts". If a contract depends on your will or ability of repaying the loan, then it's not a self-enforcing contract. Somebody need to provide a collateral. It doesn't make sense for you to put up a 1001 Ether collateral to take 1000 Ether loan.
With smart property represented on the Blockchain you will be able to put up your car or apartment as a collateral for a loan, then it can be made self-enforceable. But it's not there yet.
The only way I can see for it to be implemented is with your own token, which will be devaluated each time somebody not repaying the loan in full.
You appear to have replied to the wrong person in your first post in this thread. Did you mean to say that @drdeca, not @mannykannot, misunderstands the purpose of gas?
Augur's native token is not what is used to create markets, Augur's token is Called REP (short for Reputation) and holders of the token actually serve as reporters that serve as the basis of our decentralized oracle system.
We created a few resources to explain how REP works including how REP holders are rewarded for reporting the truth/punished for reporting lies. We created a short two minute animated video to explain this process you can check out here: https://www.youtube.com/watch?v=sCms-snzHk4.
Additionally there is a great resource going into much further detail about Reputation as well as an infographic to visually illustrate the process here: http://www.augur.net/blog/what-is-reputation
Finally feel free to reach out if you have any other questions. The Augur Alpha is out at http://demo.augur.net and our code is on github at http://github.com/augurproject
One real big problem is nobody wants to bet using shady highly volatile currency like Bitcoin or Ether. I'd much prefer USD markets, Vitalik has some ideas about making stable coins that track USD. Hopefully that works out.
I don't really understand the mechanism by which it is meant to track the price of the basket of currencies, but I haven't seen many criticisms of it?