1. An apparatus for optically embedding hidden data in a source image, wherein the hidden data is updateable in real-time, comprising: a) optical masks bearing a data image and an encoding carrier image, either or both of which may be updated in real-time; b) optical components for convolving the data image with the encoding carrier image to produce a spatially dispersed data image; and c) optical beam combiner for combining the spatially dispersed data image with the source image to produce a source image containing embedded hidden data.