Abstract: A key for a rotationally adjustable cylinder core (4) with a lock cylinder (3) containing a cryptochannel (11) freely leading into the peripheral area of the cylinder core (4) and, more particularly, to a key for a cylinder core of locking systems, which is provided with a profiled region (15), which is provided with lateral recesses (such as 17, 18), facing the back of the key that is flush with the peripheral area of the cylinder core when the key is inserted, and with a notched region (13), which faces the opposite key breast, can be inserted into the central cylinder core region of the cryptochannel (11), has a round, cylindrical and, particularly, a circular, cylindrical shape, as well as milled slots, depressions or similar notches (16) disposed peripherally and axially offset in the key for arranging tumbler elements (8), which are mounted in the lock cylinder (3) and can be adjusted radially to the core center of the lock cylinder (3).

Abstract: A key for a cylinder lock has a relatively slender profile region and a bitting region of greater thickness and a generally cylindrical configuration with or without longitudinally-extending flats. The bitting recesses can be provided round this bitting region and axially therealong and the profile region can be formed with grooves milled in its parallel flanks to increase key variability.