Protector Armor

Hey guys, I’m having a blast with Halo 4. Does anyone know how to unlock protector armor? I think you can unlock a variation of it with mastering all commendations, but seeing is that might take me a lifetime I was wandering if there was another way to get the regular protector. Thanks for the input!

Also, is there a list somewhere on here of how to unlock each kind of armor?

IGN.com halo wiki