Abstract: A ball spline with detour tracks includes spline shaft, nut part movable along a longitudinal direction of the spline shaft, and balls between the nut part and the spline shaft, wherein the nut part includes nut adapted to insert the spline shaft thereinto and retainers on longitudinal sides of the nut, the spline shaft includes tracks extended along the longitudinal direction, the nut includes load track grooves formed in longitudinal direction on inner peripheral surface into which the spline shaft is inserted and non-load circulating portions formed in the longitudinal direction, each retainer includes circulating grooves on the inner peripheral surface to face the load track groove and non-load circulating portion, the balls run between the tracks and the load track grooves, and each track includes track groove formed in longitudinal direction of the spline shaft and detour tracks whose longitudinal sides are connected to the track groove.

Abstract: An apparatus for encrypting an image frame generates a key frame, performs XOR with the image frame and the key frame to generate a temporary image frame, and changes positions of blocks of the temporary image frame according to a first key to generate an encrypted image frame. An apparatus for decrypting an image frame receives an encrypted image frame, generates a key frame, changes positions of blocks of the encrypted image frame according to a first key to generate a temporary image frame, and performs XOR with the temporary image frame and the key frame to generate the image frame.