You can tell how much stake is used in creating a POS chain.
No you can't if stake has been sold and purchased, because the order of those transactions in time is entirely arbitrary and controlled by whom ever is claiming to have the stake now.
That is why PoS requires checkpoints and always online nodes with > 50% of the stake (who all agree with each other due to Nash equilibrium[1]) to avoid a Sybil attack.
[1] but the Nash equilibrium doesn't exist if one can earn more profit by shorting the coin or attacking an exchange, etc.. PoS is a mess that requires centralization. Note that Satoshi's PoW is also a mess that also centralizes as well due to the economics of mining+verification and wastes a lot of electricity (
Bitcoin is already controlled by the Chinese mining cartel), so it is sort of stalemate at this point which explains the popularity of PoS (other reason PoS is popular is it is technically easier to implement and it is much superior for controlling P&D schemes and top-down governance).
The point about checkpoints is that when your protocol depends upon them for security purposes, you might as well just throw the whole thing in the bin and use a 100% centralised service, which will be exactly as secure and a lot faster, cheaper and easier to use.
Bit harsh.. There are many other benefits to a decentralised system, that 'needing-one-32-byte-checkpoint-at-first-logon' doesn't screw up.
Decentralized nodes provide DDoS resistance, higher availability and uptime. But a centralized controller can provide decentralized nodes. The significant advantages of decentralization derives from decentralizing control so that failure modes are removed that revolve around disagreements or vested interests.
You can see that PoS has no Nash equilibrium unless it is controlled by one "winner take all".
I'm with spartacusrex. The ultimate test is for someone to pull of one of these (theoretical) attacks and catastrophically and irreparably damage the network in some way, or at least prove that one of the attacks can be used to consistently and successfully attack the network and/or individual users. Until this test is completed, I'm going to assume that POS and other variations (DPOS) is sufficiently secure.
Also, it would be in everyone's best interest if POS was broken sooner rather than later while valuations are low. So please, if you have a guaranteed attack, go ahead and do it and prove POS useless.
PoS systems have already been attacked, I believe it was by an exchange. But that is not even the main point, which apparently you are also not cognisant of.
The main point is that the centralization required to obtain a Nash equilibrium in PoS is the attack. A centralized system is a political and vested interest leverage against everyone who uses the system. For example, the centralized control can veto feature changes, such as how the Chinese mining cartel has vetoed a block size increase for Bitcoin so they can ostensibly force transaction fees high to fatten their profits.
Still waiting.................
The ill-informed hubris that n00bs slobber on threads is incredulous.
The 50% attacks have already occurred numerous times for PoS and PoW coins. You are just blinded because you are not looking at all forms of "attack". Typical myopia of n00bs (non-experts) who haven't conceptualized all the issues thoroughly. Live and breathe this stuff for years as monsterer, smooth, and myself have and then you may start to have the foresight that we have. We would simply appreciate a bit more respect for the effort we have invested.
I am respectful to those who respect those who invest effort. This is called a meritocracy. I put the mirror in the face of weekend warriors who disrespect those who have done their homework.