Token holders vote for 21 block producers. Pretty much all of these block producers have to be controlled by the same malicious party so that an invalid transac

Token holders vote for 21 block producers. Pretty much all of these block producers have to be controlled by the same malicious party so that an invalid transaction could go through unnoticed. (In fact I think even more than 21 nodes will track the network, as runner-ups are rewarded also to some extent) Malicious block producers, when noticed, are voted out of the system by token holders probably for ever. Unlike in case of most other currencies, block producers will be actual respectable 'real world' people (but the physical location of their servers will be unknown) In fact one can say that in case of POW if an entity can get cheaper electricity than others, it can happen the mining is unprofitable for everyone except this entity, so the system can become centralized simply by fierce competition to mine efficiently. I am not saying that I know for sure which will be the more secure method in the future: I have diversified my investments into DPOS and POW based currencies (BTC, DASH, EOS)