Bitcoin Gold Hit by Double Spend Attack, Exchanges Lose Millions

However since it is a 'Bitcoin cash' type coin this will ultimately hurt bitcoin and the community as a whole. I can already see the buzz "Bitcoin double spending attack!" articles

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 interesting to see how many GPUs you'd need to pull of a double spend against BTG and if any of the other equihash coins saw a drop off during the attack.

It'd be really interesting if it wasn't a rental attack, but an invested miner just switching over to BTG to achieve the hack.

They reversed 22 blocks, the recommendation is to increase the # of confirmations to rely upon to 50. If you are trying to react to 51% attack doubling the number of confirmations only doubles the cost of attack, and the attacker likely just doubled the number of BTG they have. If they can pay the electricity/rental cost for the attack they have enough BTG to execute the attack in a cost effective manner again.

> 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 him with more new coins than everyone else combined, than to undermine the system and the validity of his own wealth.

Apparently he didn't realize that coins could quickly be transferred to other crypto and not held, so who cares about the value of the stolen goods.

[1] https://bitcoin.org/bitcoin.pdf