Abstract: The front end (7b) of the plug (7) of a cylinder lock is covered by a profiled element (5) which includes a key hole (6) whose profiled shape will only permit certain individual keys of a family of keys that can be inserted into the plug also to fit the profiled element. The profiled element includes attachment elements (5b) that have U-shaped engagement surfaces (7b') which co-act with corresponding engagement surfaces (7c) on a front part (7b) of the plug. The profiled element can be fitted to the lock in place, by turning the profiled element perpendicular to the plug axis. The profiled-element attachment elements (5b, 5b'; 7c, 7c') are inaccessible from outside the lock when the cylinder lock is fitted in place.

Abstract: A cylinder lock-key combination includes a cylinder housing (1) having arranged therein a rotatable cylinder plug (2) having a slot (3) for a key (8). Arranged on the spine of the key is coded information in the form of regions (8a, 8b) of mutually different magnetic permeability. When the key moves relative to the housing these regions cause variations in a magnetic flux generated by a magnetic body (5k) and passing the key slot (3). A differential field plate (5) arranged in the housing and incorporated in an electric circuit, which also incorporates a bridge coupling, is arranged to convert said magnetic flux variations to momentary changes in resistance in the electric circuit, causing the bridge coupling to become unbalanced so that an electric pulse train corresponding to the coded information is generated in the circuit. This pulse train is sensed and evaluated by means, for example, of a data processing device. The invention also relates to a cylinder lock and a key for said combination.