visprint (http://www.tastyrabbit.net/visprint/)
By Goizeder Ruiz de Gopegui
Copyright: Goizeder Ruiz de Gopegui
License: GPL

visprint is a program to produce visual fingerprints. This code was
written by Ian Goldberg, based on an idea by Hal Finney, in a post to
the coderpunks mailing list. The most excellent color enhancements
were added by Raph Levien.  David Johnston Ported the program to
Windows 95 console mode and added a bunch of nice features.
Soren Andersen developed the png and transparency code.

I decided to rescue the code from the oblivion of the
internet, clean it up and maintain it. As far as I know, there is no
copyright infrigement, since the code has always been free and available
in the net and the previous authors are properly acknowledged. (Please, don't sue me ;)

Take a look at the man page for more information about visprint.