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Learn Ethereum smart contract programming

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Re: Learn Ethereum smart contract programming

#151

Post by ekidd »

kbody wrote: post #109

The sad reality of Ethereum: 1. Bitcoin is slow and expensive, Ethereum is the future 2. Ethereum software has security hole, gets hacked 3. Ethereum fans say it's an experiment there are lots of things that will transform Ethereum (Casper/PoS, Raiden, zkSNARKs, Enterprise Alliance) 4. Low price getting pumped by Ethereum Foundation & big-holder affiliates 5. Back to #1 We've seen it happen again (DAO) and again (Par…

> 2. Ethereum software has security hole, gets hacked

The last time this was discussed on Hacker News, I found this comment particularly instructive: https://news.ycombinator.com/item?id=14810008

It points out a great many fundamental issues with the Solidity contract language. Basically, the language design sounds extremely amateurish and it appears to have ignored everything we've learned about security in the last 30 years. Samples:

- "Operators have different semantics depending on whether the operands are literals or not. For example, 1/2 is 0.5, but x/y for x==1 and y==2 is 0."

- "All state is mutable by default (this includes struct fields, array elements, and locals). Functions can mutate state by default"

- "Order of evaluation is not defined for expressions. This in a language that has value-returning mutating operators like ++!"

I wouldn't trust a Solidity smart contract with $100.

Re: Learn Ethereum smart contract programming

#152

Post by patrickaljord »

simias wrote: post #145
halflings wrote: post #25

Earlier quoted context omitted.

That's like saying legal contracts are a disaster because we do not live in an ideal world where lawyers don't do mistakes, and there are no legal loopholes. Granted, bugs are much more common than legal loopholes, but in the same way an operating system's APIs and constraints are tested until it becomes reliable enough for other people to rely on it, I can see some standard types of contracts (in the same way as in…

I think I'm going to end up pasting this link in all discussions surrounding Ethereum: https://en.wikipedia.org/wiki/Letter_and_spirit_of_the_law >When one obeys the letter of the law but not the spirit, one is obeying the literal interpretation of the words (the "letter") of the law, but not necessarily the intent of those who wrote the law. Conversely, when one obeys the spirit of the law but not the letter, one is…

> "The code is law" is a wet dream for a dystopic authoritarian state and I don't understand why anybody, much less actual coders, would think that's a good idea.

How is that dystopic and authoritarian? Looks like you're throwing a bunch of buzz words for shock value with little argument to back it up. We already trust code as contract everyday every time you make a payment through SSL (anyone who lived through the 90's and early 2000's remembers how people were scared to death of online payment security and now it happens every millisecond). Ethereum is just a distributed version of that with no middle man, that is to say it can fail like SSL can when compromised but it doesn't mean we should throw it out the window just because it could sometimes fail. By that logic we should still be cavemen and forget about any technology ever.

> "Thank you for subscribing to our contract for your $2 weekly subscription. By the way through a clever loophole obfuscated in our code the amount actually doubles every week. "

I hope you're aware that the exact same thing happened with these indexed loans where people weren't aware that interests could fluctuate with time, right?

Re: Learn Ethereum smart contract programming

#153

Post by justinfrankel »

ym705 wrote: post #122
justinfrankel wrote: post #94

Earlier quoted context omitted.

yeah, it's completely broken. which normally you would fix, but oh look too late!

Thanks for your comment and it's fixed thanks to a hard fork ;)

right on, the tutorial was interesting (even for someone with little interest in all things blockchain :)

Re: Learn Ethereum smart contract programming

#154

Post by judah »

staticelf wrote: post #96
maehwasu wrote: post #80

Earlier quoted context omitted.

The big thing that helped me was to understand that: smart contract == program stored on the blockchain The blockchain tracks the program's state and handles state transitions. Read-only functions are free to execute; functions that alter the program's state cost Ethereum to run. That's it. It's quite powerful and conceptually simple, but the phrase "smart contract" seems to throw a lot of people off.

I've got that now but that worries me even further. I don't trust myself to create bug-free programs and are in the belief that it's impossible. The issue with the system is that you can't update the contract, which means it has to be perfect when it is distributed on the blockchain. 1 bad mistake away from loosing maybe the entire wallet and it seems to already have happened several times. The main issue that it is…

>> "I don't trust myself to create bug-free programs and are in the belief that it's impossible."

And the recent hack exploited exactly this: a harmless-looking piece of code that turned out to have a serious bug allowing re-initialization of a wallet. The exploit allowed black hats to take control of certain unpatched wallets.

Re: Learn Ethereum smart contract programming

#155

Post by justadeveloper2 »

throw2016 wrote: post #112

The problem with crypto coins is some have bought in and thus are vested making balanced discussion impossible. We see even with something as trivial as choice of programming language some can become very religious in their support. When money becomes involved expecting rational discussion is perhaps naive. Money is a social construct that needs societal consent and a framework to manage it that is accountable to the…

Not only is it a social construct, but the concept of money took thousands of years to evolve, with fits and starts, to what it is today. No matter what, some new technology isn't going to just show up all of a sudden and completely revolutionize what is an intrinsic component of human civilization. To think otherwise is to be taken in by scammers.

I know that current money systems have flaws and are manipulated by the elites. Crypto won't end up being any different in that regard, however. Inflation is a tactic utilized within the current flawed system to move wealth to the top without your bank balance displaying the change. Cryptos will end up having their own flaws to be exploited.

Re: Learn Ethereum smart contract programming

#156

Post by kordless »

BaronSamedi wrote: post #99
staticelf wrote: post #17

The problem I see with Ethereum is that it is way too complex. I have read perhaps at least 10 times on their home page without even understanding what it does, what problems it solves etc. This is the sole reason why I don't think it will be successful in it's current state. With most successful tech or services or whatever the core idea is often super simple to grasp and you can instantly see the benefit. I don't s…

Ethereum reminds me of what happened to the web: the desire to add code. The blockchain by itself wasn't good enough so Ethereum added code to it, just like HTML wasn't good enough so people added applets, Flash, and JavaScript. I understand why they would want to do this but I think it gets the priorities wrong. It prioritizes features and functionality over security and reliability. Given how hostile the Internet h…

Bitcoin has code. The language is called Script. It lacks loops, however.

Re: Learn Ethereum smart contract programming

#157

Post by ekidd »

merijnv wrote: post #130
mbrock wrote: post #119

Earlier quoted context omitted.

The belief that Turing machines aren't amenable to formal verification is a hobgoblin that shows up in every thread like this, but it's not real. Of course there are limited formalisms that make certain types of verification easier, but proving programs has been possible since, like, the 1960s. A multisig, for example, has a finite number of states when considered under symbolic execution. A model checker can rip thr…

Sure, you CAN verify Turing machines, but verifying languages that AREN'T Turing complete is sufficiently simpler. So why not make your verification work easier by using a total language? The only real argument against that would be "we can't do what we want in a total language". I don't buy the argument that what people want to do with smart contracts requires Turing-completeness. In fact, as time goes on I become m…

Corecursion and codata are cool, and I would trust Solidity vastly more if it were a "total" functional language with no mutable state and aggressive type checking. Or if it were something more like https://www.idris-lang.org/ , where I had abundant tools to rigorously prove that nobody could steal my money.

Basically, if I'm going to spend even 5 minutes playing with smart contracts, I want to feel like the language designers were incredibly paranoid and aware of just how good modern languages can be at provability and security.

Re: Learn Ethereum smart contract programming

#158

Post by woah »

lawless123 wrote: post #144
guscost wrote: post #126

Earlier quoted context omitted.

> the takeover-the-world echo-chambers of ethereum You toss out this pejorative description, and then in the next paragraph : > When talking about engineering on such a critical subject, people should be way more responsible. This is absurd. How could it ever become critical without a lot of research and development first? I've been holding a handful of Ethereum since there was a decent dip in the price. I haven't sp…

>"I've been holding a handful of Ethereum since there was a decent dip in the price. I haven't spent much time on it and I have no good leads for program ideas yet, but if the code is buggy and I get hacked and lose my investment, that's fine. A smart contract is a project, and it could fail like any other. Don't put your retirement savings in a smart contract right now unless you're OK with losing it all. Maybe in t…

Why are you sick of hearing it? Why are you even in this thread? If ethereum is so dumb, why do you care so much?

Re: Learn Ethereum smart contract programming

#159

Post by Jabanga »

paganel wrote: post #44
omarforgotpwd wrote: post #16

Programmable smart contracts are a great idea in a world where programmers write bug free code. That world does not exist yet. Until we have near-perfect code writing AIs every new smart contract is just a disaster waiting to happen.

> That world does not exist yet With a big emphasis on "yet". Serious question: are the "halting problem" and the "yet" in your sentence dependent on each other? I.e., don't we need to first solve the halting problem before we can manage to write 100% bug-free programs?

My understanding is that the halting problem does not prevent formal proofs of Ethereum contract correctness because Ethereum contracts have gas limits that make them terminating.

Re: Learn Ethereum smart contract programming

#160

Post by woah »

kordless wrote: post #156
BaronSamedi wrote: post #99

Earlier quoted context omitted.

Ethereum reminds me of what happened to the web: the desire to add code. The blockchain by itself wasn't good enough so Ethereum added code to it, just like HTML wasn't good enough so people added applets, Flash, and JavaScript. I understand why they would want to do this but I think it gets the priorities wrong. It prioritizes features and functionality over security and reliability. Given how hostile the Internet h…

Bitcoin has code. The language is called Script. It lacks loops, however.

Dealing with the legwork around programming bitcoin script will always be at least 10x more complex than whatever it was that you wanted to program.
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