Double Spend Attacks on Exchanges

[MentalNomad]

@flavius

A little addition, the estimated attacking hashrate may be as high as 175MH:

https://www.coinotron.com/coinotron/app?action=ChartNoLogon&span=0&type=C&name=BTG

The Coinotron pool likely represents miners chasing the “highest profit” coin at any moment, not a malicious attempt.

@flavius

A side effect is the mining difficulty right after the attack is very high so the rest of the miners have hard time finding a block after the attacker leaves.

Yes, it is definitely harmful to steady miners and to the ecosystem.

@flavius

Miners, it’s important to keep mining so the cost of the attack remains as high as possible.

This is true.

@flavius

PoW change may indeed solve this but only if BTG is using an Equihash variation that noone else uses.

Also true. The PoW change means we will leave the “big pond” of Equihash power for the “small pond” of EquihashDifferent power - a pond where we are the biggest fish, so the risk will be lower (until others choose to use the same EquihashDifferent power that we do, which will bring more water into our pond.)

Also of note, our upcoming fork includes improvements to the DAA - Difficulty Adjustment Algorithm. If our Difficulty adjusts more rapidly to the incoming surge of hashpower, the participants in the surge will earn fewer “excess” coins, limiting their profit. This will also make malicious attacks more expensive. This will help protect the steady miners and smooth out the flow of blocks.