Can we switch this discussion to a more appropriate topic title and stop posting in here?
It’s creating unnecessary FUD every time it pops on the latest post lists.
The paper is proven to be debunked. This forum topic title no longer accurate.
I recommend the new topic title be called:
“Proof-of-stake network safety” or something a little more positive and geared towards all the speculative questions and answers.
I added (Debunked) to the thread title. Hope that helps.
And with this reply the offending title drops down a little further.
To answer subject in 2 lines here is how I see it, it will not cost you anything to try double-spend that is correct, but important thing to notice is that chances drops exponentially with each block.
Also it will not cost you anything to kill bitcoin network by guessing someone’s private key but chances are very slim…