Do what the manufacture recommends!
eg. Campagnolo recommend a dry taper interface and a dry bolt thread. Raceface recommend lubrication.
I can see the point of both arguments.
Grease (anti sieze compound, a specific loctite type compound or JC4) to reduce the chance of corrosion between different metals (very good point and one that I go by on non tapered interfaces).
But my interpretation
of engineering practices is that (as a generalisation) a square taper (with no manufacture information) is nothing like a splined or keyed shaft and should not be greased as this could lead to the crank moving too far up the taper thus increasing the stress on the corners of the female square taper leading to possible cracking in the future.
Even if you installed the campy cranks on a dry taper but greased the bolt and then used a calibrated torque wrench at the correct setting you will still have over torqued the bolt (because of the grease reducing the friction) and put more stress on the taper than the designers intended. Again do what the manufacture recommends!
Conversely if you installed the raceface cranks dry with a with a torque wrench the crank will not be seated on the taper far enough with the risk of play developing.
To all the other aircraft engineers. Would you grease a componant when installing it if the AMM said it should be installed dry? And I have to admit that I dont recall any square tapers on any of the aircraft that I have worked on so I have no specialist knowledge regarding square tapers on aircraft.
Personally I dont grease