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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

#121

Post by philwelch »

johndunne wrote: post #7

This is inevitable. Ethereum Classic (ETC) isn't the only currency such attacks have been successful on. The site https://www.crypto51.app/ puts the cost of running a 51% attack on ETC at ~$5k per hour. The incentive for running these attacks for profit becomes higher as the market cap of these coins increases, making long-term 'investment' in these coins nonsensical.

I wonder if there's a formula for the maximum wallet or transaction size you can safely have on a particular cryptocurrency given the cost of a 51% attack. If a 51% attack costs $5,000 per hour, you're only going to do it if you can extract more than $5,000 of value (or if your motivation is to see the world burn). In theory you might be able to set things up such that the cost of a 51% attack is necessarily greater than whatever financial gain you could get from it.

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

#122

Post by Scoundreller »

CydeWeys wrote: post #40
johndunne wrote: post #7

This is inevitable. Ethereum Classic (ETC) isn't the only currency such attacks have been successful on. The site https://www.crypto51.app/ puts the cost of running a 51% attack on ETC at ~$5k per hour. The incentive for running these attacks for profit becomes higher as the market cap of these coins increases, making long-term 'investment' in these coins nonsensical.

If you're not on the largest coin for any particular interchangeable hashing algorithm then you're susceptible to these attacks, as people from a larger coin could simply turn their hardware against you and take you out. That means: For SHA256^2-specific hardware, Bitcoin (the real one, not Cash, Gold, or SV), for scrypt, Litecoin, and for anything mined on GPUs, Ethereum (not Classic).

If a 51% attack is mounted by adding hash power, wouldn’t the existing miners on the target coin also start shutting down[1] because the competition is higher, reinforcing the strength of the attackers?

[1] or migrate from to another coin, such as the coin that the attackers left to fill their void?

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

#123

Post by AlexCoventry »

vasilipupkin wrote: post #102
matte_black wrote: post #91

Earlier quoted context omitted.

It’s not very often you get a chance to take down a currency. In 30 years from now you’ll be able to brag about how back in your day you took down entire cryptocurrencies with 51% attacks.

51% attacks are quite possibly wire fraud so I would refrain from bragging about them. More accurately, trying to double spend the coins is wire fraud.

Not if you have the consent of the counter-parties (or are the counter-parties.) It might be against some other law to manipulate the price like that, though.

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

#124

Post by nickpsecurity »

nostrademons wrote: post #67
hacker_9 wrote: post #3

Amazing, this blockchain technology really just keeps on giving. I have to say, it's quite entertaining to watch. It's pretty much a car crash happening in slow motion at this point. At least it provides something else to nerd joke about by the watercooler that isn't brexit for once.

That's what it was like in 2016. I remember seeing the headline for the DAO hack on HN back then and thinking "Wow, good thing I didn't invest in this Ethereum thing". Someone had told me about it in 2015, I took a quick glance and passed thinking "Looks like a scam." Then 2017 happened and the joke was on me. Then 2018 happened and the joke was on them again. New technologies are always shitshows when they get start…

"New technologies are always shitshows when they get started. "

A key difference is most of the new techs like Internet, email, Paypal, and so on improved on what people already had in a way that delivered obvious value. They also came with problems. Whereas, nobody I know in real life wants the drawbacks of these cryptocurrencies that come with giving up the benefits of their current, centralized offerings. The only folks I know out here doing crypto are speculators (esp day traders). That's the difference.

Now, if they wanted to solve those problems, they'd start with whatever tech/law/orgs already worked, identify their problems, and then mitigate them using proven methods. So, we're looking at credit unions, non-profits, or public-benefit companies chartered to make sure they do specific good things and don't do specific bad things. The most important stuff at least. These can be in the licenses and contracts, too, for re-enforcement. Then, centralized systems with decentralized checking of what's exchanged a la SWIFT all using existing high-performance tech we know how to secure. Open protocols and agreements for how disputes will be resolved in situations using decentralized mode with experts from both centralized and decentralized models weighing in on that. I've been talking about that in Gerard's threads on Lobsters:

https://lobste.rs/s/wxqkyj/bitcoin_s_stupendous_power_waste_...

https://lobste.rs/s/opge2r/electricity_consumed_by_bitcoin#c...

I can't find the other ones sense the search feature is limited.

"they're so desperate for a solution that they put up with a solution that basically doesn't work. "

That's true when there's a need. This is part of a hype cycle pushing stuff people don't need to replace stuff that would meet their needs fine. Accelerated by massive amounts of money being thrown all over this area. Totally different kind of thing. The stuff that bubbles, bankruptcies, and broken dreams are made of.

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

#125

Post by bdonlan »

Scoundreller wrote: post #122
CydeWeys wrote: post #40

Earlier quoted context omitted.

If you're not on the largest coin for any particular interchangeable hashing algorithm then you're susceptible to these attacks, as people from a larger coin could simply turn their hardware against you and take you out. That means: For SHA256^2-specific hardware, Bitcoin (the real one, not Cash, Gold, or SV), for scrypt, Litecoin, and for anything mined on GPUs, Ethereum (not Classic).

If a 51% attack is mounted by adding hash power, wouldn’t the existing miners on the target coin also start shutting down[1] because the competition is higher, reinforcing the strength of the attackers? [1] or migrate from to another coin, such as the coin that the attackers left to fill their void?

With a 51% attack the additional hash power is not visible on the chain until the attack is triggered to perform a rollback.

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

#126

Post by orblivion »

pryce wrote: post #55
orblivion wrote: post #11

Earlier quoted context omitted.

Being only somewhat familiar, I wonder this: Why don't clients have a simple rule against accepting changes to history that are more than one or two blocks old?

Other people have answered this from a more technical perspective. Philosophically, what the distributed blockchain is , is an agreement for adjudicating whose record (eg list of transactions) should be agreed on as "the valid one". If you already have a different, reliable external way of deciding this question, that is (arguably) conceding that you didn't need a distributed blockchain in the first place. EDIT: I've…

What I described would be part of the rules of system (or at least certain players). It just says "no changing history after X point".

If anything, relying on an outside source is what we're doing now. Coinbase and others are telling us that they detected something and I haven't heard anybody question them. (And I'm assuming they're not lying). Though that's not to say the blockchain will be changed by this information.

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

#127

Post by bouncycastle »

jancsika wrote: post #108
jonahx wrote: post #81

Earlier quoted context omitted.

Would you mind elaborating on this for someone unfamiliar?

Imagine all the Bitcoin miners out there right now using their ASICs to do extremely efficient hashing in the hopes of generating a block reward. Let's didactically suppose there are 100 such miners total. Now imagine Dinkycoin comes along and releases their cryptocurrency that uses the same hashing mechanism for the block reward. Initially they have the block difficulty level pretty low as there aren't that many peo…

But if they throw hashpower on Dinkycoin, wouldn't Dinkycoin's difficulty increase? If the difficulty for Dinkycoin re-targets more aggressively, then Dinkycoin would quickly gain more security in the process!

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

#128

Post by dragontamer »

Scoundreller wrote: post #122
CydeWeys wrote: post #40

Earlier quoted context omitted.

If you're not on the largest coin for any particular interchangeable hashing algorithm then you're susceptible to these attacks, as people from a larger coin could simply turn their hardware against you and take you out. That means: For SHA256^2-specific hardware, Bitcoin (the real one, not Cash, Gold, or SV), for scrypt, Litecoin, and for anything mined on GPUs, Ethereum (not Classic).

If a 51% attack is mounted by adding hash power, wouldn’t the existing miners on the target coin also start shutting down[1] because the competition is higher, reinforcing the strength of the attackers? [1] or migrate from to another coin, such as the coin that the attackers left to fill their void?

51% attackers mine in secret.

Basically, you spend your coins today, while controlling a 51% share. When everyone else's 49% hash-power creates 98 blocks, your 51% share will create 102 blocks.

But secretly. That's the key. Now that your chain is +4 ahead (or wait even longer and become +10 ahead), you can spend your coins on the public chain. Then, you publish your 102 alternative blocks (which barely adds any hash power to the chain), and spend your coins again on the 2nd chain.

A 51% is the end-all-be-all for a cryptocoin. If you're vulnerable to the 51% attack, the coin is effectively worthless.

-----

The only way to beat a 51% attack is to build more hash power than the attackers. IE: Prevent the attackers from getting to 51%.

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

#129

Post by zeroname »

trophycase wrote: post #116
zeroname wrote: post #60

Earlier quoted context omitted.

The only way to profit is to double-spend, so you'll have to buy or already own a substantial amount of those junk coins and then sell them. After you performed the attack, those coins that you now could theoretically sell again may be suspended from trading or should at least trade at a substantially lower price. Add in the opportunity cost of exercising such an attack and it's not clear that you could turn a profit…

Unless there is margin trading, then you can simply just short the coin.

Is there margin trading on any of these junk coins? Doesn't seem like a good idea to offer something like that, given the relatively low liquidity/volume.

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

#130

Post by acdha »

nostrademons wrote: post #67
hacker_9 wrote: post #3

Amazing, this blockchain technology really just keeps on giving. I have to say, it's quite entertaining to watch. It's pretty much a car crash happening in slow motion at this point. At least it provides something else to nerd joke about by the watercooler that isn't brexit for once.

That's what it was like in 2016. I remember seeing the headline for the DAO hack on HN back then and thinking "Wow, good thing I didn't invest in this Ethereum thing". Someone had told me about it in 2015, I took a quick glance and passed thinking "Looks like a scam." Then 2017 happened and the joke was on me. Then 2018 happened and the joke was on them again. New technologies are always shitshows when they get start…

> The last was in 2003, 14 years after the Internet was introduced - put on the Bitcoin timeline, that's 4 years in the future, assuming cryptocurrency is adopted as fast as the Internet

This is a common comparison but it’s based on a very dubious equation of the history. By 2003, the internet had transformed many industries — e-commerce was in the billions of dollar range (Amazon’s earliest business lines had been profitable for the better part of a decade by then); millions of people used it daily for tasks like research or customer service, software or media downloads, etc. Mainstream media and ads were full of URLs not just for internet companies but for existing companies which were increasingly focused on the internet.

In contrast, Bitcoin has almost no reason for anyone to care about it other than speculation and the few people who do use it regularly for anything else are largely using it as a replacement for PayPal with worse customer protections.

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