Uh.. any single person who owns more than 50% of the computation can basically mess everything up, unless I'm mistaken? So, maybe you mean 3 independent partie

Uh.. any single person who owns more than 50% of the computation can basically mess everything up, unless I'm mistaken? So, maybe you mean 3 independent parties.. but what's to stop those 3 people from colluding for their own benefit, etc.. Anyway you need a hell of a lot more than 3 to run it.