Text-Graphics Character CAPTCHA Home Page
The Text-Graphics Character (TGC) CAPTCHA is a CAPTCHA designed for
a low-resolution user interface, namely the dumb terminal.
A CAPTCHA is a Completely Automated Public Turing Test to tell Computers
and Humans Apart. They're cool! Go to
http://www.captcha.net for more
The TGC CAPTCHA Project is a collaboration between
Chanathip (Meaw) Namprempre
and Matthew Dailey.
Source code to add TGC CAPTCHAs to the OpenSSH client and server, version
3.6.1, can be downloaded here:
Note: this code is purely experimental at this point, and is not approved
by the Secure Shell (secsh) Working Group or anyone else. By downloading
this code, you agree that any loss or
damage resulting from the use of this software is your problem, not ours.
To install, unpack the archive, read the README, and follow the instructions.
You will also need the OpenSSH version 3.6.1 source code, available
A short paper, submitted to IEEE TENCON,
on the TGC CAPTCHA is also available: A Text-Graphics
Character CAPTCHA for Password Authentication.