A cylinder lock with a rotating tumbler pin, a sidebar, and a slider has a keyway with a ward projection into the center of the bitting area of a key blade received by the keyway. The tip of each rotating tumbler pin seats on the bitting surfaces remaining to the sides of this center ward of the key, and the tumbler pins that are engaged by the bitting on the side of the key blade do not seat on more than half of the width of the blade. Half the pin width is removed from each tumbler pin near the tip thereof. The key has a bitted section at which one or more bittings are formed and a non-bitted section bitting that is devoid of bitting. The bittings extend at a constant depth to an edge of the key blade.