It would be an exponential difficulty growth for several thousands iterations (the base difficulty would be equal to the network difficulty at the fork time). So, one would have to possess really good hashing power. I think that mathematically this attack is even less possible than wellknown 51% attack. More precisely this attack would have possibility 100% but the computation time would be HUGE.
You should sand box it before making those statements. This is exactly the vector that was opened up.
~BCX~
It appears some draino/coin hybrid has been hit with a difficulty of 55 million and just so happens to use KGW. Would you happen to know anything about this? Please tell me I didn't look away and miss something!
