Still asking out of desire to learn: How has it been shown to be flawed? With what kind of experiments? Which are the flaws? How to they manifest them self (e.g. how could you exploit them with PoS but not with PoW)?
One problem: You fire up your blockchain software and it reaches out over the internet to find other servers and ask them if they have a copy of the blockchain.
But how does in know which copy is the real one and not one cooked up by someone like me showing I own half the coins?
With proof of work you can choose the one with the most work in it and that's hard to fake as the real bitcoin blockchain has billions of dollars worth of computer work in.
With proof of stake it's hard. If there is no real cost, fakers can make thousands or millions of fake chains and how do you know which is the 'real' one?
There are potential solutions but it's tricky. Like if you have www.stake-coin.com point to the real one, what if someone manages to take over the domain?
You bootstrap the pos chain onto the pow one, so you have your trivially checkable first part. After that it.s not exactly trivial to fake the whole chain without holding validators private keys (remember, they had stake in pow chain).
Im kinda at a loss about what other vectors of attack possible, hard to find any digestible info, and pos protocol designs are really complex.
I am not searching down all the whitepapers for you, if you truly want to learn then you will need to dig into the myriad mathematician's white papers against Proof of Stake.
