[tinkerrr]

I am curious to know what types of "big big risk" POS presents. As far as I can tell, there are several POS cryptocurrencies today and they seem to work fine. The Ethereum team claims to modify their POS approach to avoid known issues like the 'nothing at stake' problem. But it would be interesting to know what other possible risks you're talking about.

[runeks]

Non-proof-of-work consensus always ends up depending either on trusted third parties or majority vote. Anyone can create a valid-looking non-PoW chain in a short time, and there's no way to separate valid chains from each other. In Bitcoin, when you want to bootstrap, you connect to n nodes and if just a single node is honest you will get the right chain. For non-PoW, if there's disagreement, you have to trust either a majority on what the right chain is, or add trusted nodes that overrule a majority vote. For proof-of-work there will always be a chain with most work done, provided >50% of miners are honest (hard dependency).

I have written a bit longer on the subject here: https://runeksvendsen.github.io/blog/posts/2017-06-14-bitcoi...

[Frogolocalypse]

They work fine if there's trust.