Abstract: An improved locking mechanism is provided with a fixed outer cylinder and at least two side-by-side rows of resiliently urged pins disposed in a staggered relation therein. A face plate contains a nonrotatable key slot in angular disorientation to the pins and a key is provided with a plurality of biased grooves forming inclined planes to depress the pins as the key, imposed in an inner cylinder, are rotated together through the plane of the pins. The inner cylinder is connected to a bolt actuating linkage in a conventional manner. A pin bar having a plurality of reversely biased grooves forming inclined planes in the same profile as the key is disposed in a longitudinally extending channel in the inner cylinder. The face plate is formed of an anti-drill metal secured to an intermediate housing by crimping in a peripheral area which is inaccessible between the intermediate and an outer housing.