Abstract: The invention relates to a cross-sectional profile (1) for a flat key or the keyway of a cylinder lock, comprising a back surface (2), a first lateral surface (4) and a second lateral surface (4?), wherein the lateral surfaces (4, 4?) extend in the vertical direction to the back surface (2), the lateral surfaces (4, 4?) are arranged offset to one another by a distance (5), which varies along their extension, and the outline of the cross-sectional profile (1) defines a preferably substantially rectangular base profile (6), and wherein the lateral surfaces (4, 4?) each extend at least in sections along sinusoidal profiling lines (7, 7?), wherein the centerlines (8, 8?) of the profiling lines (7, 7?) lie within the base profile (6). Further, the invention relates to a flat key (16) with such a cross-sectional profile (1) and a cylinder lock with a keyway (13) for receiving such a flat key (16).

Abstract: The invention relates to a cross-sectional profile (1) for a flat key or the keyway of a cylinder lock, comprising a back surface (2), a first lateral surface (4) and a second lateral surface (4?), wherein the lateral surfaces (4, 4?) extend in the vertical direction to the back surface (2), the lateral surfaces (4, 4?) are arranged offset to one another by a distance (5), which varies along their extension, and the outline of the cross-sectional profile (1) defines a preferably substantially rectangular base profile (6), and wherein the lateral surfaces (4, 4?) each extend at least in sections along sinusoidal profiling lines (7, 7?), wherein the centerlines (8, 8?) of the profiling lines (7, 7?) lie within the base profile (6). Further, the invention relates to a flat key (16) with such a cross-sectional profile (1) and a cylinder lock with a keyway (13) for receiving such a flat key (16).