In the optical implementation of image encryption using random phase e
ncoding proposed by Refregier and Javidi the random phase mask is not
band limited. Speckle noise can thus destroy optical reconstruction of
the encrypted images. We demonstrate encryption of speckle-free kinof
orms by smoothed random phase masks. Optical verification of the encry
pted images is shown. (C) 1996 Society of Photo-Optical Instrumentatio
n Engineers.