A lock and key system and device for doors. It is a removable door locking system or lock and carry kit, including: a door blank disposed in a door frame; a first elongated member passing through the latch hole and extend therefrom; a second elongated member disposable in the lock body hole and extending therefrom; a flange extending radially from a first end of the elongated member and stops passage of the first end through the lock body hole of the door; an aperture through the second elongated member; and/or a detachable lock coupleable to the aperture and stops passage of the second end through the lock body hole when coupled to the aperture. The door blank may include a lock body hole through the door blank that receives a lock body and a latch hole through the door blank and in communication with the lock body hole.