ACM-SIAM Symposium on Discrete Algorithms (SODA '01)
Washington D.C., January 2001
We present a method to notarize a paper document. This method computes a set of features from the page, inputs these features into a hash function, digitally signs the output, and then prints the resulting signature on the page. The notarized document is self-contained: verification does not require reference to online information.