> By the logic of that article asymmetric cryptography doesn't, because the value equal to what's protected by the key is magically wasted somewhere. Of course,

> By the logic of that article asymmetric cryptography doesn't, because the value equal to what's protected by the key is magically wasted somewhere. Of course, that isn't true, because it's not possible to break asymmetric cryptography by brute force with expenditure equal to whatever is protected. Same applies to PoS. Not quite. He's arguing that MC = MR implies that PoS is really PoW through obscure means. There's more to securing PoS than asymmetric cryptography -- namely, you have to convince everyone that your keys (and the coins attached to them) are legitimate, and not the next guy's keys and coins on a fork. Convincing people of this isn't a cost-free task, especially if there's wealth to be accumulated through convincing more and more people that your coins are legitimate, and everyone else's conflicting coins on different forks are not. This game of convincing people that your fork is the true fork is exactly what stake-grinding is. Given a choice, and no a priori knowledge, which history of the PoS chain is the true history? What would convince you that one is legitimate, and the other is not? The article argues that the act of convincing you is, itself, a form of PoW. After all, without PoW, looking at the chainstate isn't convincing -- if you have staked coins today, you could easily create a fork of the chain history where everyone else stopped spending except for you. Without no 3rd party way to verify if that actually happened, you could go around trying to bribe people to accept that your subsequent transactions on this fork are the chain's "true" transactions. There's many tactics for doing this -- you could go on Twitter and spam everyone; you could organize events and rallies; you could even take malicious actions and disable your rivals. You and everyone trying to do the same thing would be in competition to convince everyone else that your fork is the "true" fork. But regardless of the tactics, all of them require expenditures on your part in the forms of time, energy, health, stress, etc. Hence the "PoW by obscurity" argument. But at the end of the day, you'd be unwise spend any more than you'd expect to receive in return because of MC = MR. Here's a concrete example. The reason you can tell that there's a lot more belief that ETH is the true Ethereum fork, and not ETC, is because ETH has a much higher PoW score than ETC. Miners can choose between ETH and ETC to mine, and they mine the one whose tokens are worth more. ETH is worth more because more people value it. Therefore, PoW is a proxy measurement of the social consensus -- more people believe in ETH than ETC. If ETH were PoS at the time of the split, it would be a lot less obvious from the chainstate which one people would choose to use. Both chains' participants would try to make it look like their chains had more users by some other means. But the point in the article is that those "other means" are not only costly actions, but also the marginal cost each fork can afford for these actions is, in equilibrium, equal to their respective marginal revenues.