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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

#121

Post by [deleted] »

drb91 wrote: post #74
gamblor956 wrote: post #57

Earlier quoted context omitted.

Bitcoin and other cryptocurrencies require even more trust than normal currency. With a normal currency transaction, you need only trust at most 2 other entities entities: your counterpart to the transaction and the government issuing the currency. With a blockchain, you still need to trust the counterparty, but now you also need to trust that the coders have properly designed and programmed the system, and that the…

I think there are fundamentally different ways we're talking about trust: you "only" need to trust a government, you "only" need to trust a bank, vs trusting a certain proportion of miners to be following the same bitcoin specs you are, as well as trusting that people will value it tomorrow. Both of bitcoin and government-issued currency requires trust, and building that trust is fundamentally difficult, depending on…

[deleted]

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

#122

Post by s73v3r_ »

patmcc wrote: post #46
mike-cardwell wrote: post #15

Earlier quoted context omitted.

I think stealing is illegal, yes.

Is this stealing by whatever definition police/the courts currently use? Isn't it an intentional part of the design of a cryptocurrency that decisions are made by a consensus based on hashing power? If you have 51% of the hashing power, you have control over that cryptocurrency; that's by design. Can you really steal at that point? edit: to those replying, I'm not saying this double spend is ethically fine, or not th…

Yeah. You're taking things that don't belong to you, and you're defrauding others. Regardless of the technology, those things remain quite illegal.

Courts generally frown on cutesy "gotcha" type defenses like that. See: Sovereign Citizens.

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

#123

Post by mikekchar »

49bc wrote: post #8

Satoshi really downplayed 51% attacks in his/her original whitepaper[1]: > The incentive may help encourage nodes to stay honest. If a greedy attacker is able to assemble more CPU power than all the honest nodes, he would have to choose between using it to defraud people by stealing back his payments, or using it to generate new coins. He ought to find it more profitable to play by the rules, such rules that favour h…

I think it's probably fair to say that he/she did not anticipate people spinning up a whole bunch of crypto-currencies and that those crypto-currencies would be worth something. How many coins are out there that are worth millions of dollars to people speculating? I certainly wouldn't have given that idea credence at the time Satoshi wrote the original whitepaper.

I personally thought that BTC would either be successful (in that it would be a useful currency) or that it would tank. I did not anticipate people dumping piles of money into it to speculate on its value. I certainly did not anticipate a bunch of wannabe coins sitting on millions and providing practically no value to anyone.

It's a testament to the number of people who are desperate to get rich. I probably should have taken a cue from the lotteries...

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

#124

Post by snarf21 »

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…

I think one of the other issues is that each transaction that they are double spending can be worth so much. If each transaction was maxed out at say $100, the incentive to double spend the transaction becomes smaller. Obviously that changes a lot about the costs of mining and transactions, just saying the bigger a single transaction or value in a single address, the larger the likelihood of an attack. We see the same things with cash, they only run the "counterfeit" pen on $20 or larger.

Just wondering if there is some kind of crypto currency where the transactions had a max of some kind. Would the difficulty be able to be much smaller and blocks every minute (since there would be so many more to transact)? This isn't well formed, just off the top.....

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

#125

Post by [deleted] »

spookthesunset wrote: post #60
mike-cardwell wrote: post #15

Earlier quoted context omitted.

I think stealing is illegal, yes.

> I think stealing is illegal, yes. Code is law, bro. These fine chaps simply gathered enough resources to execute a slightly different code-path than before. The folks whose value was stored in Bitcoin Gold should have read the source code before committing any funds to the blockchain. Had they done so, it would have been very clear that this feature was baked right into the source code. And yes, this is sarcasm....…

[deleted]

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

#126

Post by mehrdadn »

onecooldev24 wrote: post #105
drexlspivey wrote: post #98

Earlier quoted context omitted.

What a lot of people in the thread seem to be missing is that when you receive a huge payment you can require a higher amount of confirmations to accept it. High enough that it would make the 51% attack unprofitable.

you can split the payment to multiple small amounts.

Confused... I thought the claim was about receiving and not sending?

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

#128

Post by s73v3r_ »

georgemcbay wrote: post #27
tedunangst wrote: post #21

Earlier quoted context omitted.

Wherever the exchange is?

Does wherever the exchange is recognize Bitcoin Gold as legal tender? The issue seems a lot more complex than either "of course this is illegal" or "of course this isn't illegal". I'm certainly not arguing in favor of either of those positions.

Is it suddenly not illegal if someone takes my TV instead of my cash?

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

#129

Post by verbatim »

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?

> Crypto currencies are worthless unless they have an enormous amount of hashing power behind them.

I think this is only true if you assume that crypto-currencies must be based on proof-of-work algorithms.

What about proof of stake systems?

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

#130

Post by oh_sigh »

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.

Even finding a single double spend attack that only double-spends 1 satoshi would be enough to destroy bitcoin.
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