fractal fingerprint generator.

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Visprint release 2.1 is now available for download with several enhancements.

This version features several bugfixes, a new color pattern and the option of using different hash functions as input (the checksum length is no longer limited to 32 characters).

Special thanks to Jan Merka for all the feedback that led to this version.

Visprint is being used in NASA's Virtual Magnetospheric Observatory website!!

Jan Merka, a researcher at VMO, has included visprint as eye-candy for the data query interface in NASA's VMO website.


Visprint makes cool fractal fingerprint png images based on the contents of any file. The image will be different for almost every file with even slightly different contents. Visprint uses the IFS fractal generation process, pioneered by Michael Barnsley. It is a way to create images which are self-similar to infinite depths. In other words, the picture is made up of smaller versions of itself.

So... What about security?

Visprint is just a "toy" program that generates cool graphics. The purpose is to serve as a fun graphic complement to checksums. In no way whatsoever should it be used as a stand-alone security tool. It's not intended to be a substitute for any file checker. Even though it can be used to check differences in files and it uses cryptographic hash functions (md5, sha1, sha256...) as it's input, it has not been designed nor tested with heavy security use in mind.


visprint is "free" software released under the GNU General Public License (GPL).


Goiz "Samhain" Ruiz de Gopegui
GPG Public Key: samhain.asc

A note on the history of visprint code

The original visprint 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 made a port for Win95 console mode and added a bunch of nice features. Soren Andersen developed the png and transparency code.

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


The current version of visprint is 2.1
  1. Source Code: visprint-2.1.tar.gz
    gpg signature: visprint-2.1.asc
    md5 checksum: visprint-2.1.md5
    visprint sha1 image: visprint21sha1.png

  2. Slackware 11.0 binary package: visprint-2.1-i686-smhn.tgz
    gpg signature: visprint-2.1slack.asc
    md5 checksum: visprint-2.1slack.md5
    visprint sha1 image: visprint21slacksha1.png

  3. Old versions can be reached here.


v2.1 (28 november 2006):
 	- Added the option of using different hash functions as input (-l switch)
	- Added the option of using an alternate color scheme by flipping RGB to BGR (-c switch)
	- Polished and fixed the grayscale color scheme.
	- Renamed the previous -c switch to -a (Area coloring scheme).
	- Fixed a bug in the transparency code.
	- Updated the man page and the help screen.
	- Some minor bugfixes and code cleanups.
Thanks to Jan Merka for the feedback on this version.

More information in the full changelog


md5, no options md5, white background
md5, transparent on black bg md5, 4 area coloring
sha1, semi-grayscale
with -b70 background value
sha1, alternate coloring


  1. Visprint in Perl, by Flavio Poletti.

  2. Solaris Freeware Project, by Steve Christensen. Here you can find binary packages of visprint for SPARC/Solaris 2.5-10 and x86/Solaris 8-10

  3. NASA's Virtual Magnetospheric Observatory has included visprint as eye-candy in it's data query interface.

  4. The page of the Visprint Win95 console mode port by David Jonhston (1999). Thanks David for your support!


Suggestions, bugreports, help requests, patches and new ideas about visprint are welcomed.


last modified: Mon Jun 22 21:55:35 CEST 2009