153k Ether Stolen in Parity Multi-Sig Attack • Hacker News Board

Re: 153k Ether Stolen in Parity Multi-Sig Attack

#341

Post by hackinthebochs » Thu, Jul 20, 2017, 12:23 AM UTC

vocatus_gate wrote: post #271

csomar wrote: post #67

Earlier quoted context omitted.

There are mixers where you can get close to not being traced and then can move through monero and then to bitcoin.

Monero is the ONLY cryptocurrency where full privacy is enforced by default. No mixers, no opt-in mode, no super-nodes, no tumblers, it's all obfuscated by default. I'm very bullish on Monero long-term.

What I don't like about monero, and why I think it'll ultimately lose to another anon product, is that the transaction history is written to the blockchain, albeit in obfuscated form. But there is no proof on the bounds of what a sophisticated blockchain analysis can uncover given enough information. Roughly speaking, its conceivable that given enough transaction information downstream from a transaction of interest might reveal a "most likely" pairing of an address with a transaction. Or perhaps a global analysis of the monero blockchain along with traditional blockchain analysis could reveal a most likely pairing of all transactions with addresses. The point is that without such a proof I'm not sure how much people will trust it compared to a protocol with such a proof (say zcash). Your exposure to future analysis is essentially indefinite.

Re: 153k Ether Stolen in Parity Multi-Sig Attack

#342

Post by sjy » Thu, Jul 20, 2017, 12:26 AM UTC

ryandvm wrote: post #172

cookiecaper wrote: post #125

Earlier quoted context omitted.

Won't happen. People need to believe that the justice system will hear their pleas and consider factors on-balance, and then proceed in fairness. In real law, there are several potential overrides available to stop egregiously unfair outcomes that would otherwise be legally valid (estoppel, unconscionability, etc.). People will not accept a system that does not have the appearance of fairness (regardless of its actua…

Not sure why you're being downvoted because you're exactly right. The crypto-anarchists love to say "the code is the law", but the reality is that losing your retirement savings because somebody forgot to mark a method private is a pretty shitty outcome. For all its warts, a legal system backed by a jury of your peers is still the best way of sorting out the actual intent of a contract when the shit hits the fan.

This is a very US-centric perspective: in most common law countries, jury trials have been all but abolished for contractual interpretation cases.

Re: 153k Ether Stolen in Parity Multi-Sig Attack

#343

Post by bduerst » Thu, Jul 20, 2017, 12:26 AM UTC

Pulcinella wrote: post #84

sbierwagen wrote: post #44

Earlier quoted context omitted.

Damn, you're right. And if people use smart contracts to do things that are technically allowed, but have unexpected downsides, we should have a review system in place where impartial third parties review the contract language. Two people should be assigned to speak for and against the unexpected behavior, and then maybe a panel of 12 regular citizens could render the actual verdict.

This is the central, glaring flaw in cryptocurrencies to me. Transferring "value" for goods and services is really more of a social problem than a scientific/engineering one. Money is a social technology that solves a social problem. Cryptocurrency is a engineering technology in search of a problem to solve.

Yep, I've heard a few pitches involving bitcoin or blockchains that came across as a hammer pivoting in search of a nail.

Re: 153k Ether Stolen in Parity Multi-Sig Attack

#344

Post by resf » Thu, Jul 20, 2017, 12:27 AM UTC

cesarb wrote: post #266

oh_sigh wrote: post #173

Earlier quoted context omitted.

Yes, and that 'feature' of block chains is never really touted by blockchain supporters. Basically, if 51% of the network think you have too much money, they can just take it from you with no recourse available.

> Basically, if 51% of the network think you have too much money, they can just take it from you with no recourse available. That's not how it works. Even if you had 99.99% of the hash rate, you still have to work within the rules of the chain, so a "give me your money" without a valid signature would still be rejected as invalid by every full node (and you just wasted your hashing power). What having 51% or more of…

It seems to me that large blockchains^ are some of the most stable social structures in existence. The rules of Bitcoin have been in place for 8 years with only minor modifications, despite huge sums of money passing through the system.

This compares very favourably with other social structures, such as nation states, especially 8 year old nation states.

^ Large as in Bitcoin and Ethereum, smaller networks are much easier to manipulate.

Re: 153k Ether Stolen in Parity Multi-Sig Attack

#345

Post by [deleted] » Thu, Jul 20, 2017, 12:27 AM UTC

davidgerard wrote: post #261

kbenson wrote: post #235

Earlier quoted context omitted.

I think a big part of the complaint is about the implicit assumption that because people are smart, and have experience with cryptography, they necessarily have the experience to design a sane and safe programming language given their goals. They did put themselves way out there, and that takes ambition, but also hubris. I wish they were able to figure out which one was driving them at certain points a bit better, as…

Actually, I think Solidity being designed to turn bad node.js coders into bad smart contract coders was key to Ethereum's success. I've written a book on this (hit upload five minutes ago! release Monday!) which hammers on this point (and all the stuff surrounding this issue). I think Solidity is actually designed with worse is better in mind, because Ethereum is the first smart contract platform that anyone actually…

[deleted]

Re: 153k Ether Stolen in Parity Multi-Sig Attack

#346

Post by pdkl95 » Thu, Jul 20, 2017, 12:27 AM UTC

grandalf wrote: post #257

pdkl95 wrote: post #170

Earlier quoted context omitted.

> personally reviewing the code. With the insane decision to use a Turing-complete language, the contract's behavior undecidable . You don't even know if the contract will halt . Limited "gas" (execution time) isn't the solution, because the lesson of the Halting Problem isn't that a program might not terminate. Even if the program halts within a finite time (or "gas"), the behavior of the program on the current inpu…

These are good points. What if the default behavior of a contract was to reset the world to its previous state if the program does not terminate within 30 seconds? Arguably unclear termination semantics would be a good reason not to trust a contract. Ideally trust mechanisms would exist such that closed source contracts were trustable via a pure insurance-based mechanism.

> if the program does not terminate within 30 seconds?

As I attempted to say in my previous comment, undecidability[1] isn't limited to deciding if a program will halt (or even the weaker question of if it will halt in a given finite time). Recursively enumerable[2] languages that require a Turing machine to automate have an intrinsic complexity (i.e. any Turing-complete language). This isn't a "work harder to solve it" level of complexity; some behavior will always be undecidable.

You might experience this problem in the traditional form of the "Halting Problem" where the question "Will this program halt?" may be answered with "I don't know, it's still running" in addition to "yes" or "no". However, this level of complexity can also cause unexpected output due to subtle interactions inside the program that are difficult to predict from the source. Some behaviors are provably unknowable.

You can avoid this problem by using a simpler class of language. Regular languages (which "regular expression" match[3]) are safe, as are deterministic context-free[4] languages. You may find the lack of loops limiting.

[1] https://en.wikipedia.org/wiki/Undecidable_problem

[2] https://en.wikipedia.org/wiki/Chomsky_hierarchy#Type-0_gramm...

[3] basic regexp, not PCRE or other language-sepcific extensions!

[4] https://en.wikipedia.org/wiki/Context-free_grammar#Undecidab...

Re: 153k Ether Stolen in Parity Multi-Sig Attack

#347

Post by eropple » Thu, Jul 20, 2017, 12:27 AM UTC

wheelerwj wrote: post #328

eropple wrote: post #244

Earlier quoted context omitted.

One of the more important skills in this craft is the combination of intuition and knowledge to know when you don't know something well enough to achieve the goal. The difference between "ambition" and "hubris" is small but critical.

That's a valid point. But its hard to be humble when you work on something that was designed to topple national banks.

Then you shouldn't be working on it. If you can't be humble, you should not be working on things that can hurt people because you're creating risk for them that they can't actually measure. (It's why I consciously avoid such projects; knowing one's propensity to arrogance makes it unethical not to.)

If it's important, you need to be good. If it's very important, you need to be good and sure.

Re: 153k Ether Stolen in Parity Multi-Sig Attack

#348

Post by grandalf » Thu, Jul 20, 2017, 12:28 AM UTC

notahacker wrote: post #316

grandalf wrote: post #247

Earlier quoted context omitted.

> Chargebacks are a blessing when you need them and a curse when you receive them, but something that the economy has deemed a necessary evil mostly because there are a lot of fraudsters in the world This is an excellent point, and I think it's an example of how an institutional mechanism evolved to help address fraud. There's absolutely no reason to think chargebacks would not come to exist if commerce were dominate…

I don't think anyone doubts that smart contracts can be written that allow for a trusted third party to effectively reverse a payment, especially not in Turing-complete languages. I think the point is that if mutability and trusted third party oversight is actually usually a necessary and desired fraud prevention feature in a payments system, there's probably not huge demand to replicate all that using blockchains wh…

> I think the point is that if mutability and trusted third party oversight is actually usually a necessary and desired fraud prevention feature in a payments system, there's probably not huge demand to replicate all that using blockchains whose most-touted virtue is immutability and trustlessness

I'd argue that rarely in meatspace finance is the consensus mechanism considered separately from the other aspects of a currency that matter. Consensus at changing aspects of a currency typically fall upon a government organization which has its own politically-driven, non-transparent consensus mechanism.

In meatspace, we have things like bankruptcy law and its derivatives to help preserve order when contracts unwind.

Of course, provisions for unwinding an agreement in an orderly way are part of any sophisticated financial deal. Meatspace contracts bootstrap on existing legal interpretations and regulations, but those things mainly add convention, repeatability, and predictability to the behavior of the contract.

So when (if ever) does the consensus mechanism in a fiat currency actually matter? I'd argue that it matters when the sh*t hits the fan, when there is an economic shock and widespread demand for action. This is when the stupidest decisions get made and the rule of law is the weakest.

Hedging against these stupid decisions adds tremendous cost and friction to meatspace financial deals. While it may feel right for regulators to "make whole" certain parties, that is not necessarily in the interest of the rule of law. It's far better if the various contingencies are addressed before the fact so that they can be priced in accurately.

Systems like Ethereum have the potential to create (over time) a set of useful and inviolable rules that can allow transactions to take place without the costly hedging against stupid, knee-jerk decisions by regulators.

In order for parties to willingly enter into contracts, the desirable state is not that later some wise overlords will take a look at the contract and make a fair decision about some yet-to-be-determined aspect of it. The desirable state is for the contract itself to be 100% trustworthy.

Of course, with the infamous hard fork, Ethereum failed at this once, but ETC exists now in tandem, so the two governance approaches can compete on their merits.

Distributed blockchain consensus give us a more transparent consensus mechanism than ever before, which is crucial to democracy. On this bedrock, it will likely be possible to create a world where we truly have the rule of law, not the rule of men.

The point here is not that smart contracts are "law", it's that the execution of a contract should take place in an unbiased VM, and the transparency and consensus mechanism of ETH ensures that.

Re: 153k Ether Stolen in Parity Multi-Sig Attack

#349

Post by rjurney » Thu, Jul 20, 2017, 12:29 AM UTC

I can't even understand what you are all talking about. Crazy kids. I'm not even kidding. Usually I can figure out what the topic of conversation is if I'm not familiar with it, but in this case I'm like three degrees removed from comprehension.

Sounds like this is all probably dot com bullshit, but maybe something genius will come out of it that is unforeseen now.

Re: 153k Ether Stolen in Parity Multi-Sig Attack

#350

Post by shurcooL » Thu, Jul 20, 2017, 12:31 AM UTC

earlz wrote: post #25

Here's the root error I believe: https://github.com/paritytech/parity/blob/master/js/src/cont... The initWallet function should have been marked internal, but was instead not marked. Unmarked functions default to public in Solidity, so anyone can call that function and reinitialize the wallet to be under their control

Please be aware that you can press Y before sharing a link to make it a permalink. The link you shared points to master branch, which will change over time, so the line number you pointed to will have something else.

Based on the time of your post, I suspect you meant to link to:

https://github.com/paritytech/parity/blob/4c32177ef3f4521c66...