In this demonstration we use the above image to illustrate two types of watermarking. First, visible watermarking. And second, we illustrate how invisible watermarking can be used for the purpose of image authentication.

The invisible watermarking technique illustrated here is described in greater detail in "A public key watermark for image verification and authentication," by P. W. Wong, in the Proceedings of the International Conference on Image Processing, which was held in Chicago in October 1998.