Here is the main problem with Proof of stake
https://bitcointalk.org/index.php?topic=615843.msg6751334#msg6751334PoS need some form of trust like checkpointing or web of trust solutions to solve the problem which undermines the trustless nature of cryptocuncies. IMO opinion we should aim for algorithms that make crryptocuncies more trustless i.e. removing dependence of pools etc
Actually that is BS.
Nothing At Stake Problem summarized here by gmaxwell
Quote:
"In PoW when you attempt to mine you must expend energy and so you should only mine on a consensus which is likely to be the surviving one if you want your work to not be wasted. In PoS the same is not true, and an optimally rational PoS miner will attempt to concurrently mine all forks which he does not hate."
1. Gmaxwell is a Major BTC advocate , it is like walking over to Dunkin Donuts store and asking how the Krispy Kreme Doughnuts taste from across the street, don't expect an untainted answer.
2. In PoS , you still expend Electricity & Bandwith, it is just PoS is so much more economical to run than PoW, no one considers it a cost.
In PoS, all of the coins compete against everyone else's coins to find consensus of the longest chain with the highest difficulty,
this increases the Difficulty # Higher than anything you could produce alone by staking your coins alone on an offline fork
Since when on an offline fork , your Difficulty # will always be lower than the main chain.
So basically the Nothing At Stake Problem , is really just a Stupid Myth.
Because staking on the online fork makes it impossible , for your Same coins to create enough difficulty on an offline fork concurrently to matter,
As the online fork will always have it's difficulty plus your own if you mine both concurrently.
PoS & Pow are both protected by this simple fact, Longest Chain with the Highest Difficulty Wins.
Except some PoS Specs also include coin age which further strengthens its security.
