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We can confirm that there was a successful 51% attack on Ethereum Classic

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Re: We can confirm that there was a successful 51% attack on Ethereum Classic

#281

Post by jki275 »

acdha wrote: post #278
jki275 wrote: post #275

Earlier quoted context omitted.

No, it's good enough if precautions are taken. If you apply a moderate amount of care, your identity is not hard to protect when using it. There are a variety of ways to have private transactions across either the public internet or other networks. There are a variety of coins that use tor, for instance. It doesn't have to be bitcoin either. My point was that if you can avoid cashing out to fiat using well known gate…

> It only becomes an anonymity problem if you are careless or if you cash out using known KYCd gateways. This means you can't use it for currency transactions, with anyone you don't trust, or on any system which might be compromised by the authorities you're trying to evade. If you ever make a mistake, all of that not only won't help you but will be strong evidence of intention. There are very few threat models where…

That's not what that means.

It means you need to operate inside the cryptocurrency ecosystem instead of counting on cashing out all the time, or you simply use any of the many non-regulated means to cash in and out of the ecosystem.

That's becoming more and more possible to do.

Re: We can confirm that there was a successful 51% attack on Ethereum Classic

#282

Post by jki275 »

garmaine wrote: post #280
jki275 wrote: post #272

Earlier quoted context omitted.

That's an assertion that I haven't seen any data to back. I don't believe either (a) or (b) applies to either xtz or to ada, though ada hasn't yet deployed POS. I can well believe that there are broken POS implementations, there have been a lot of broken implementations of a lot of things in the space -- but claiming every system is known to be broken or cannot be analyzed is a very bold claim to make.

How would you expect a statement that certain mechanisms have become too complex for review to be backed by data? What observations could I convey to you over a HN comment other than “go look for yourself”? For a write up of the general, unavoidable problems of proof of stake, see Andrew Poelstra’s proof of stake FAQ.

I gave you two of the best known examples of proof of stake that there are. The Tezos team has done it and it's been running for about a year now. The Cardano team is doing it, and I'll link their paper below.

As far as Poelstra, that's a rather old document. A great deal of research has been done in the field since.

Cardano's paper: https://eprint.iacr.org/2016/889.pdf

Re: We can confirm that there was a successful 51% attack on Ethereum Classic

#283

Post by garmaine »

jki275 wrote: post #282
garmaine wrote: post #280

Earlier quoted context omitted.

How would you expect a statement that certain mechanisms have become too complex for review to be backed by data? What observations could I convey to you over a HN comment other than “go look for yourself”? For a write up of the general, unavoidable problems of proof of stake, see Andrew Poelstra’s proof of stake FAQ.

I gave you two of the best known examples of proof of stake that there are. The Tezos team has done it and it's been running for about a year now. The Cardano team is doing it, and I'll link their paper below. As far as Poelstra, that's a rather old document. A great deal of research has been done in the field since. Cardano's paper: https://eprint.iacr.org/2016/889.pdf

No new research can overturn the basic fact that proof of stake claims to do is impossible. It's perpetual motion machine. You can make proof of stake schemes more complicated, but it doesn't gain you actual security, just obscurity. You can't actually achieve the desired outcome of proof-of-work properties for a stake-based consensus mechanism.

What has happened instead is that the basic / easy to analyze systems were broken, and so complications were added that defeated the simple attacks, but really just make attacking it more complicated. But there's no asymmetric advantage against attackers here -- a similarly complex attack can be made for any proof of stake scheme.

Re: We can confirm that there was a successful 51% attack on Ethereum Classic

#284

Post by alkonaut »

hippich wrote: post #277
alkonaut wrote: post #97

Earlier quoted context omitted.

Shouldn’t any sale/transaction be considered “not final” (goods can’t be shipped, for example) until the official chain has progressed to a point where you can be sure the cost of producing a censored fork is higer than the transaction in question? That is: you buy something expensive then it might not ship for a month or two. I guess you could buy a hundred gadgets at $100 each from a hundred places in one day and t…

you can't predict that - the alternative chain is mined privately and it is a matter of amount at stake how long this mining will continue.

But in the publicly visible (longest, official) chain, can't I estimate the effort that was used to mine from a certain transaction up to the head? Say the transaction I want to hide is b, then the attacker would need to mine a longer alternative chain (c', d'...). If transaction b was for $1000 and we can estimate that the mining of the visible chain c...f is at least $2k with a conservative estimate, can't we estimate that the attackers chain c'...g' must cost something at least vaguely proportoinal to that as well? Is it not even possible to make a conservative guesstimate of cost-vs-chain-length?

    a

Re: We can confirm that there was a successful 51% attack on Ethereum Classic

#285

Post by jki275 »

garmaine wrote: post #283
jki275 wrote: post #282

Earlier quoted context omitted.

I gave you two of the best known examples of proof of stake that there are. The Tezos team has done it and it's been running for about a year now. The Cardano team is doing it, and I'll link their paper below. As far as Poelstra, that's a rather old document. A great deal of research has been done in the field since. Cardano's paper: https://eprint.iacr.org/2016/889.pdf

No new research can overturn the basic fact that proof of stake claims to do is impossible. It's perpetual motion machine. You can make proof of stake schemes more complicated, but it doesn't gain you actual security, just obscurity. You can't actually achieve the desired outcome of proof-of-work properties for a stake-based consensus mechanism. What has happened instead is that the basic / easy to analyze systems we…

If you want to claim it's a perpetual motion machine, you're going to have to prove that claim.

There are a whole lot of very smart people who disagree with you.

Re: We can confirm that there was a successful 51% attack on Ethereum Classic

#286

Post by acdha »

jki275 wrote: post #281
acdha wrote: post #278

Earlier quoted context omitted.

> It only becomes an anonymity problem if you are careless or if you cash out using known KYCd gateways. This means you can't use it for currency transactions, with anyone you don't trust, or on any system which might be compromised by the authorities you're trying to evade. If you ever make a mistake, all of that not only won't help you but will be strong evidence of intention. There are very few threat models where…

That's not what that means. It means you need to operate inside the cryptocurrency ecosystem instead of counting on cashing out all the time, or you simply use any of the many non-regulated means to cash in and out of the ecosystem. That's becoming more and more possible to do.

> It means you need to operate inside the cryptocurrency ecosystem instead of counting on cashing out all the time, or you simply use any of the many non-regulated means to cash in and out of the ecosystem.

None of which has any bearing on the problems I mentioned earlier. If you're worried about a repressive government, the odds are high that other people in the system are compromised and will help reveal your identity. Those “many non-regulated means to cash in and out” are similarly not readily available and extremely likely to be compromised as well. People sometimes act like mixers solve this problem but they aren't effective against attackers who can see lots of traffic and even if they worked as well as advertised, simply using one is going to be considered proof that you were doing something illegal and attempting to hide it.

Finally, as we're already seeing you have the problem that in a repressive country simply being able to maintain software security is an unsolved problem: consider what the odds are that someone will manage to maintain perfect security of their devices and client trying to find software which is considered illegal and will attract attention simply by searching for it.

Read anything about the history of people living under regimes with black market economies and ask what a blockchain is adding other than a gift-wrapped transaction history for the authorities. It's simply irresponsible to tell people that you're not exposing them to more risk in the hope that it'll make some money for you.

Re: We can confirm that there was a successful 51% attack on Ethereum Classic

#287

Post by garmaine »

jki275 wrote: post #285
garmaine wrote: post #283

Earlier quoted context omitted.

No new research can overturn the basic fact that proof of stake claims to do is impossible. It's perpetual motion machine. You can make proof of stake schemes more complicated, but it doesn't gain you actual security, just obscurity. You can't actually achieve the desired outcome of proof-of-work properties for a stake-based consensus mechanism. What has happened instead is that the basic / easy to analyze systems we…

If you want to claim it's a perpetual motion machine, you're going to have to prove that claim. There are a whole lot of very smart people who disagree with you.

The paper by Poelstra has details.

Re: We can confirm that there was a successful 51% attack on Ethereum Classic

#288

Post by jki275 »

garmaine wrote: post #287
jki275 wrote: post #285

Earlier quoted context omitted.

If you want to claim it's a perpetual motion machine, you're going to have to prove that claim. There are a whole lot of very smart people who disagree with you.

The paper by Poelstra has details.

I read it. It's old, and the issues in it have been addressed. There have been several years of research since that paper was released. I've pointed you to an academic paper that addresses the issues.

I'm done with this discussion as you're simply repeating the same things over and over.

Re: We can confirm that there was a successful 51% attack on Ethereum Classic

#289

Post by jki275 »

acdha wrote: post #286
jki275 wrote: post #281

Earlier quoted context omitted.

That's not what that means. It means you need to operate inside the cryptocurrency ecosystem instead of counting on cashing out all the time, or you simply use any of the many non-regulated means to cash in and out of the ecosystem. That's becoming more and more possible to do.

> It means you need to operate inside the cryptocurrency ecosystem instead of counting on cashing out all the time, or you simply use any of the many non-regulated means to cash in and out of the ecosystem. None of which has any bearing on the problems I mentioned earlier. If you're worried about a repressive government, the odds are high that other people in the system are compromised and will help reveal your ident…

Mixers are hardly the only form of dealing with anonymity. We have multiple privacy coins and ways of getting in and out of them that do a very good job of dealing with the problems you mention if you are concerned about mixers for some reason.

Somehow, people in China still manage to get on the internet, how do you think that happens? As it happens, the internet was designed to route around censorship, and it's done a very good job so far.

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