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Deconstructing the DAO Attack: A Brief Code Tour

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Re: Deconstructing the DAO Attack: A Brief Code Tour

#21

Post by [deleted] »

xenophonf wrote: post #16
fabled_giraffe wrote: post #6

I know I'll get napalmed for saying this, but why is this all over HN? Why are people obsessed with cryptocurrencies? It's bad enough that those with sufficient computing speed/power can already rip off the stock market; why does the world need another way for people to rip each other off? Since we've determined over history that some people will take advantage of weakness for their own gain, no matter what system yo…

Even though I disagree with some of your conclusions, I personally have no problem with your comment except for the very first and very last sentences. I generally downvote people who complain about submissions or about their comments being downvoted, which I view as unproductive.

[deleted]

Re: Deconstructing the DAO Attack: A Brief Code Tour

#22

Post by irln »

fabled_giraffe wrote: post #6

I know I'll get napalmed for saying this, but why is this all over HN? Why are people obsessed with cryptocurrencies? It's bad enough that those with sufficient computing speed/power can already rip off the stock market; why does the world need another way for people to rip each other off? Since we've determined over history that some people will take advantage of weakness for their own gain, no matter what system yo…

Because it is an insanely interesting problem to try and solve technically.

That is, a medium of exchange is essential to a modern economy and yet how to objectively regulate the supply of that medium of exchange without exploitation can be considered somewhat of a paradox. The quest is to solve the paradox via ever evolving technological solutions.

Re: Deconstructing the DAO Attack: A Brief Code Tour

#23

Post by tmalsburg2 »

willtim wrote: post #4

Modelling financial contracts in an imperative event-driven paradigm just seems like an accident waiting to happen. EDIT: To the downvoters, if you disagree, I would very much like to understand why, please reply with a comment. EDIT2: My position is that it is very difficult to reason about correctness and maintain invariants in a highly imperative setting. IMHO, it would be more desirable to use a declarative, or f…

This is the most insightful comment about this incident that I have seen so far. The problem is that the Etherum system uses an imparative language to describe smart contracts. This opens the door very wide for the kind of bugs that led to the theft of $200M from The DAO. The correct solution would probably have been to design a domain-specific declarative language that provides abstract building blocks for smart contracts. This would have allowed to hide the procedural complexity in the interpreter and contract bugs like the present one would not have been possible. Even if there was a problem, it could likely be fixed in the interpreter leaving the contracts and the blockchain untouched! This means that a lot of unanticipated problems would not have been fatal for the contracts. The problem of the current approach is that it conflates the business logic and it's implementation thus increasing the burden for contract authors and increasing the attack surface.

In many other domains, a suboptimal choice of language paradigm would just add some extra friction but in the domain of smart contracts it can lead to catastrophic failures. Many people claim that the cause of the present disaster is just a faulty contract and that the Etherum system is working correctly. Some even say that the present case shows how well the technology is working. But willtim's comment makes it clear that there may be a fundamental problem with Ethereum. I wonder whether the imparative paradigm was a conscious design choice or something that just happened because the developers didn't even realize that it was a design choice.

Edit: I wrote this before willtim's added his edit 2.

Re: Deconstructing the DAO Attack: A Brief Code Tour

#24

Post by jacquesm »

rahimnathwani wrote: post #18
willtim wrote: post #4

Modelling financial contracts in an imperative event-driven paradigm just seems like an accident waiting to happen. EDIT: To the downvoters, if you disagree, I would very much like to understand why, please reply with a comment. EDIT2: My position is that it is very difficult to reason about correctness and maintain invariants in a highly imperative setting. IMHO, it would be more desirable to use a declarative, or f…

I didn't downvote you, but your comment left me scratching my head. You made a statement without any explanation. Care to elaborate why imperative programming is so bad here? Real-world contracts also use imperative style.

This code is very bad, without going into an exhaustive enumeration, case sensitive function names, variables with unclear scope all over the place and so on.

That it's imperative code is something that I don't think is damning by itself but all the side-effects (including side effects based on a single bit in the name of a function) really do warrant the 'accident waiting to happen'.

Re: Deconstructing the DAO Attack: A Brief Code Tour

#25

Post by TruthAndDare »

fabled_giraffe wrote: post #6

I know I'll get napalmed for saying this, but why is this all over HN? Why are people obsessed with cryptocurrencies? It's bad enough that those with sufficient computing speed/power can already rip off the stock market; why does the world need another way for people to rip each other off? Since we've determined over history that some people will take advantage of weakness for their own gain, no matter what system yo…

> It's bad enough that those with sufficient computing speed/power can already rip off the stock market

Who is getting ripped off?

Re: Deconstructing the DAO Attack: A Brief Code Tour

#26

Post by verroq »

fabled_giraffe wrote: post #6

I know I'll get napalmed for saying this, but why is this all over HN? Why are people obsessed with cryptocurrencies? It's bad enough that those with sufficient computing speed/power can already rip off the stock market; why does the world need another way for people to rip each other off? Since we've determined over history that some people will take advantage of weakness for their own gain, no matter what system yo…

Because we missed the boat and we hope the boat sinks.

Search your feelings, you know it to be true.

Re: Deconstructing the DAO Attack: A Brief Code Tour

#27

Post by vezzy-fnord »

irln wrote: post #22
fabled_giraffe wrote: post #6

I know I'll get napalmed for saying this, but why is this all over HN? Why are people obsessed with cryptocurrencies? It's bad enough that those with sufficient computing speed/power can already rip off the stock market; why does the world need another way for people to rip each other off? Since we've determined over history that some people will take advantage of weakness for their own gain, no matter what system yo…

Because it is an insanely interesting problem to try and solve technically. That is, a medium of exchange is essential to a modern economy and yet how to objectively regulate the supply of that medium of exchange without exploitation can be considered somewhat of a paradox. The quest is to solve the paradox via ever evolving technological solutions.

objectively regulate

There's your problem. Such grandiose visions might have passed for a 1930s-era technocrat, but are laughable today.

Re: Deconstructing the DAO Attack: A Brief Code Tour

#28

Post by DrJokepu »

jacquesm wrote: post #10
fabled_giraffe wrote: post #6

I know I'll get napalmed for saying this, but why is this all over HN? Why are people obsessed with cryptocurrencies? It's bad enough that those with sufficient computing speed/power can already rip off the stock market; why does the world need another way for people to rip each other off? Since we've determined over history that some people will take advantage of weakness for their own gain, no matter what system yo…

> Why are people obsessed with cryptocurrencies? Because they are interesting in a theoretical way and because real world implementations are even more interesting, they show us what the future might look like. > It's bad enough that those with sufficient computing speed/power can already rip off the stock market; why does the world need another way for people to rip each other off? That's not the intent. > Since we'…

> That remains to be seen.

Isn't this a somewhat meaningless statement? Is it possible to prove that "no matter what system you create to transfer goods, resources, services or value representing those, it will be exploited"? Is it possible to prove the contrary (that there is or could be such a system)?

It will never be seen because we will never know for sure one way or the other. Best we can do is to make educated guesses based on past experiences.

Re: Deconstructing the DAO Attack: A Brief Code Tour

#29

Post by tinco »

fabled_giraffe wrote: post #6

I know I'll get napalmed for saying this, but why is this all over HN? Why are people obsessed with cryptocurrencies? It's bad enough that those with sufficient computing speed/power can already rip off the stock market; why does the world need another way for people to rip each other off? Since we've determined over history that some people will take advantage of weakness for their own gain, no matter what system yo…

I think maybe you're a bit confused about what HN is, it is a community that gathers and discusses news that is relevant to people who are starting or funding new companies, mostly in the information technology sector.

Cryptocurrencies attract money and spawn companies, there are YC funded startups that are based around cryptocurrencies. If you're looking for refuge from them, you've gone to the wrong place, this is basically the lions den. If there's money to be made with technology, this is where it'll be discussed, no matter over whose back.

Just that it's on HN doesn't mean HN or even YC supports it. If everyone on HN would support ETH, BTC or the DAO, it'd be worth even more. It's just interesting technology with relevance to business and finance.

Re: Deconstructing the DAO Attack: A Brief Code Tour

#30

Post by willtim »

Waterluvian wrote: post #19
willtim wrote: post #4

Modelling financial contracts in an imperative event-driven paradigm just seems like an accident waiting to happen. EDIT: To the downvoters, if you disagree, I would very much like to understand why, please reply with a comment. EDIT2: My position is that it is very difficult to reason about correctness and maintain invariants in a highly imperative setting. IMHO, it would be more desirable to use a declarative, or f…

Same to you. Can you explain why you think so?

I've tried to explain my position briefly above in an edit.
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