A lock and key combination includes a cylinder rotatably disposed within a shell and a sidebar within the cylinder and movable between a locked position preventing rotation of the cylinder and an unlocked position allowing rotation of the cylinder. A slider is mounted within the cylinder for movement between a first position blocking movement of sidebar from the locked position and a second position not blocking movement of said sidebar. A key has a blade configured to be inserted into a keyway of the cylinder and includes a slider-actuating element mounted within the blade for movement with respect to the blade. As the blade is inserted into the keyway, a cam element within the keyway moves the slider-actuating element to a position engaging the slider so that further movement of the key moves the slider from the first position to the second position.