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Bitcoin Gold Hit by Double Spend Attack, Exchanges Lose Millions

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Re: Bitcoin Gold Hit by Double Spend Attack, Exchanges Lose Millions

#411

Crypto currencies are worthless unless they have an enormous amount of hashing power behind them. We could really do with a webpage with a list of crypto currencies, the hashing power currently behind them, and how much it would cost somebody to take over 50% of the network. Or does that already exist?

there is http://arewedecentralizedyet.com

Whilst that's an interesting page, it lacks the most important part of my request: "and how much it would cost somebody to take over 50% of the network"

Re: Bitcoin Gold Hit by Double Spend Attack, Exchanges Lose Millions

#412

Earlier quoted context omitted.

> If hash capacity were traded on a perfectly competitive market, then it would always make sense to rent 51% of the capacity at market rates, earn the transaction fees, and also perform a double-spending attack. There is no equilibrium point for transaction fees where this attack becomes uneconomical. The only defense is that the market for hash capacity is imperfect. At this point in time the current hashrate of th…

It is far from clear that Bitcoin will likely ever reach $70,000. That implies an approx market cap of $1,200,000,000,000 or more. Would Bitcoin ever be useful enough or generate more value than Google or several Big Energy companies combined to justify and sustain that valuation?

google value is in bitcoins

Re: Bitcoin Gold Hit by Double Spend Attack, Exchanges Lose Millions

#413

When Bitcoin was running up to $20,000, I tried to analyze the system and come to a personal conclusion about its equilibrium value, because I didn't want to miss out if it really was the currency of the future. I ended up not investing, because of the possibility of a double-spend attack. I think that cryptocurrency enthusiasts are seriously underestimating the importance of double-spending attacks to the economics…

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Re: Bitcoin Gold Hit by Double Spend Attack, Exchanges Lose Millions

#414

When Bitcoin was running up to $20,000, I tried to analyze the system and come to a personal conclusion about its equilibrium value, because I didn't want to miss out if it really was the currency of the future. I ended up not investing, because of the possibility of a double-spend attack. I think that cryptocurrency enthusiasts are seriously underestimating the importance of double-spending attacks to the economics…

Great points. The thing is though that a double spend would harm both the attacker and all others on the network. It would weaken the trust. It is a double edged sword. You would have to do the double spend without anyone noticing and then liquidate your earnings as fast as possible. With more combined hashing power this would become very hard to do.

There are a lot of problems other than double spend with the Bitcoin. Transactions fees rise very quickly because of the block size limit of about 1MB. You can't really rely on 0-confirmation transactions. The saviour lightning network in my opinion is the wrong solution to the scaling problem. It changes fundamentally how bitcoins are exchanged and steers away from the original white paper by Satoshi. Not that this is wrong... it just becomes another project altogether.

Re: Bitcoin Gold Hit by Double Spend Attack, Exchanges Lose Millions

#415
A few thoughts:

- It rubs me the wrong way to call it an "exploit" when 51% attacks are a core part of the way blockchains function.

- I'm surprised that the price for bitcoin gold isn't tanking. That's a sign that the crypto marketplace really isn't healthy right now, imo

- Conversely I'm surprised that this isn't causing a spike in coins that are more robust in regards to 51% attacks, like BTC and BURST (because they're both the majority coin in the realm of the resources they require)

Re: Bitcoin Gold Hit by Double Spend Attack, Exchanges Lose Millions

#416
post #151

Earlier quoted context omitted.

can you explain this in better words: "then it would always make sense to rent 51% of the capacity at market rates, earn the transaction fees, and also perform a double-spending attack."

I think what jhpriestly is saying is: As the market gets efficient, the price of renting mining capacity will approach the profits earned from transaction fees. So renting mining capacity will almost pay for itself, i.e. is almost free. But then you might as well rent a lot of it, like 51%, because it's allowing you to attack the chain almost for free.

Well then the buyer and seller would race to gain 51% of mining power (as its free) which will make it more expensive because of the constant biding war.

Re: Bitcoin Gold Hit by Double Spend Attack, Exchanges Lose Millions

#417
> Ordinarily, the blockchain would resolve this by including only the first transaction in the block, but the attacker was able to reverse transactions since they had majority control of the network.

Not a very precise explanation, just checking, what exactly does this mean?

I always thought the way a 51% double-spend attack worked was by broadcasting a transaction for human consumption (eg, I'll give you Y coins for Z dollars), then secretly mining your own blockchain for the N successive chains following it. After the humans have completed the human-level transactions after waiting the standard N successive blocks with no transaction conflicts, you release your own secret blockchain fork back into the public with data that contradicts the current popular one and instruct your network to ignore the competing publicly-acceptable chain. The new private one wins so long as it is equally as long as the public one which it should be because you have more compute power than the rest of the public.

Is that basically what happened here?

Re: Bitcoin Gold Hit by Double Spend Attack, Exchanges Lose Millions

#418

When Bitcoin was running up to $20,000, I tried to analyze the system and come to a personal conclusion about its equilibrium value, because I didn't want to miss out if it really was the currency of the future. I ended up not investing, because of the possibility of a double-spend attack. I think that cryptocurrency enthusiasts are seriously underestimating the importance of double-spending attacks to the economics…

If the scenario you laid out actually pans out it would be very good for Bitcoin, because there is a lot of free energy in the world but it is highly distributed.

The dominant form of mining would be utility companies and individuals redirecting excess electricity generated from their renewable electric power generators, during off-peak hours and spikes in generation, to mining, and the constituents would be both numerous and globally distributed, owing to the wide geography areas across which renewable energy resources are found.

Re: Bitcoin Gold Hit by Double Spend Attack, Exchanges Lose Millions

#419

Earlier quoted context omitted.

> If hash capacity were traded on a perfectly competitive market, then it would always make sense to rent 51% of the capacity at market rates, earn the transaction fees, and also perform a double-spending attack. There is no equilibrium point for transaction fees where this attack becomes uneconomical. The only defense is that the market for hash capacity is imperfect. At this point in time the current hashrate of th…

It is far from clear that Bitcoin will likely ever reach $70,000. That implies an approx market cap of $1,200,000,000,000 or more. Would Bitcoin ever be useful enough or generate more value than Google or several Big Energy companies combined to justify and sustain that valuation?

People said the same thing about $1,000 when it reached $35. in about 6 months, bitcoin will be 10 years, so considering that it went from $0 to $20,000 in those 10 years, so as my statement say, it's not without reason to expect it to reach $70,000 in the next 5 years.

People like to compare bitcoin to gold, which has an estimated current market cap of $6,000,000,000,000. Will gold ever generate more value than Google or several Big Energy companies combined with more than a factor 10? Or does it hold value simply because it's rare?

Re: Bitcoin Gold Hit by Double Spend Attack, Exchanges Lose Millions

#420

Earlier quoted context omitted.

Bitcoin hasn't been useful as a currency for a long time. I don't think that's a good measure for determining how an event might affect bitcoin price.

speak for yourself, only thing I cant pay is my mortgage. I have a shift card, bought tacobell with bitcoin.

You didn't buy tacobell with bitcoin unless Taco Bell quoted you a price in BTC...
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