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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

#111

Post by dbt00 »

nemo1618 wrote: post #97
bunderbunder wrote: post #64

Earlier quoted context omitted.

So, that's an interesting pair of ideas, in that it gets me thinking that any Bitcoin-style cryptocurrency might ultimately be doomed by its own design. Shooting from the hip: They've go this 51% vulnerability that is well known and hypothetically cannot be truly closed. Instead, we rely on the idea that mounting such an attack would be "too expensive". But at the same time, the cost/benefit of mounting such an attac…

On the other hand, there will be people who have a vested interest in preventing such attacks. If you own a lot of BTC, a successful attack can drastically lower the value of your assets, so it makes sense to deploy some of that capital to secure the network. And of course this goes even more so for business in the crypto space that rely on BTC remaining secure. One example of this sort of behavior is in mining. We t…

Spending capital to build hash capacity to protect an existing holding in BTC is inherently deflationary. Instead of "you need to spend money to make money" aka inflation/interest/growth, you have to spend money to keep money, which always reduces your holdings over time and turns the entire network over to companies that produce hashing capacity (hardware manufacturers, power companies).

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

#112

Post by s73v3r_ »

cachvico wrote: post #23
jacquesc wrote: post #17

Earlier quoted context omitted.

So it's not a complete waste of natural resources because it helps secure "the chain"?

Exactly. We should stop using the word "waste" to describe the energy consumption of the Bitcoin miners. It's not waste if it serves a purpose. The service it provides is to guarantee the integrity of the blockchain without the requirement of a central authority.

"It's not waste if it serves a purpose. "

It's an open question as if it actually does serve a purpose, though.

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

#113

Post by sanxiyn »

dragonwriter wrote: post #99
mike-cardwell wrote: post #84

Earlier quoted context omitted.

That graph doesn't tell me how much it costs to launch a 50% attack. Maybe I'm just lazy, but I want a table with the name of the crypto currency in one column, and the cost in USD to launch an attack in another column.

> but I want a table with the name of the crypto currency in one column, and the cost in USD to launch an attack in another column. Doesn't the cost depend on who you assume the attacker is? The required hashing power doesn't have the same acquisition and operating costs for all potential attackers.

True, but even crude order-of-magnitude estimate would be useful.

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

#114

Post by mikeash »

drexlspivey wrote: post #34
jacquesc wrote: post #17

Earlier quoted context omitted.

So it's not a complete waste of natural resources because it helps secure "the chain"?

Would you ask the same question if the world run 100% on renewables? If not, it seems that your argument should be "we should accelerate our transition to renewables" instead of "bitcoin spends too much power". Also they pay for all the energy they spend so what exactly is the problem? Do you see vegans complain for the resources spent to raise animals?

The problem is that energy is priced far below costs at the moment, due to a large proportion of the costs being externalized.

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

#115

Post by dragonwriter »

tehsauce wrote: post #110
tlarkworthy wrote: post #92

Earlier quoted context omitted.

I think the argument is that by doing a 51% attack you undermine the market value so you never get the rewards. This makes sense, but only for the leading crypto coin. As we see here today, you can 51% attack smaller coins, which should imply an increase in the value of Bitcoin from consolidation.

The spooky thing that this made me realize, is that if anyone did find a vulnerability in bitcoin (or any cryptocurrency) is that they would have a greater incentive to only slowly leech off the system, because they will be able to siphon out much more over time than if everyone panics over security. The weapon is no good unless it's secret.

Assuming you want to make money directly, sure. If you want to harm a community in which the currency is widely used, the incentives are different.

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

#116

Post by s73v3r_ »

XR0CSWV3h3kZWg wrote: post #6

more details here: https://forum.bitcoingold.org/t/double-spend-attack-on-excha... Bitcoin gold was a fork to try and decentralize mining. It changed to a proof of work that is supposed to be ASIC resistant. It looks like the typical situation is mining by GPU for equihash (BTG PoW). BTG hashrate is at ~30MH/s at the moment, where Zcash's hashrate is at ~486MH/s. I don't have the numbers off hand, but it'd be interes…

"It changed to a proof of work that is supposed to be ASIC resistant."

These are the absolute worst. All they're doing is causing the cost of graphics cards to go up.

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

#117

Post by madeofpalk »

mike-cardwell wrote: post #12

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

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

#118

Post by Taek »

jhpriestley wrote: post #83

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…

In the bitcoin system, miners make literally billions of dollars a year protecting the network. Any successful attack on the bitcoin network is going to massively erode confidence, reduce the price, reduce the usage, and therefore reduce the value of all that single-purpose, bitcoin-only hardware.

Large miners don't want to see Bitcoin get attacked because it destroys their income and de-values their incredibly expensive hardware. This is also why miners won't just let you borrow their hashrate for a while - it's a big issue if you use that hashrate to undermine their cash cow.

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

#119

Post by manigandham »

nemo1618 wrote: post #97
bunderbunder wrote: post #64

Earlier quoted context omitted.

So, that's an interesting pair of ideas, in that it gets me thinking that any Bitcoin-style cryptocurrency might ultimately be doomed by its own design. Shooting from the hip: They've go this 51% vulnerability that is well known and hypothetically cannot be truly closed. Instead, we rely on the idea that mounting such an attack would be "too expensive". But at the same time, the cost/benefit of mounting such an attac…

On the other hand, there will be people who have a vested interest in preventing such attacks. If you own a lot of BTC, a successful attack can drastically lower the value of your assets, so it makes sense to deploy some of that capital to secure the network. And of course this goes even more so for business in the crypto space that rely on BTC remaining secure. One example of this sort of behavior is in mining. We t…

That's a great way to lose all your capital, or force someone else to. You will probably not outspend a focused attacker or nation-state.

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

#120

Post by Taek »

drexlspivey wrote: post #71
bunderbunder wrote: post #64

Earlier quoted context omitted.

So, that's an interesting pair of ideas, in that it gets me thinking that any Bitcoin-style cryptocurrency might ultimately be doomed by its own design. Shooting from the hip: They've go this 51% vulnerability that is well known and hypothetically cannot be truly closed. Instead, we rely on the idea that mounting such an attack would be "too expensive". But at the same time, the cost/benefit of mounting such an attac…

> They've go this 51% vulnerability that is well known and hypothetically cannot be truly closed. Instead, we rely on the idea that mounting such an attack would be "too expensive". But at the same time, the cost/benefit of mounting such an attack is fairly easy to estimate using public data - all you really need to know is the cost to get to 51% and stay there for a given amount of time, which you can infer by monit…

Attacks can hit multiple parties simultaneously. So you need to account for that as well and make sure an attacker doing a sweeping attack that includes you is still not incentivized.

Luckily, there are deeper incentives protecting large asic mined chains such as bitcoin.

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