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COTCHA 70326-CCOTCHA - $0 Version 70326-C
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(c) 2007 Jason Silver

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COTCHA is a challenge-response script which inserts numeric sequences into your forms. The user
must retype the numeric sequence before the script will allow the form to be submitted.

Installing COTCHA consists of the following:

1. Choosing a random six digit number
2. Chossing the type of COTCHA code that's generated
3. Uploading the cotcha.cgi to your cgi-bin and setting permissions
4. Modifying your form(s) to use COTCHA
5. Modifying your form processing script(s) to use COTCHA

Here's How!

1. Using a text editor like textpad, or notepad, open cotcha.cgi

2. Make changes to the variables at the top of the file:
my $antispam_password = 575789; # a 6 digit numeric password
my $image_magick = 0; # this will create an image of the password instead of a text password
my $based_on_time = 1; # set to zero to have the cotcha based on the user's IP address.

3. Save your changes, and use an FTP program to uplaod the script in ASCII format (VERY IMPORTANT!)
Set the permissions on the file to be executable. (755). For more information, go here:

4. Open your form(s) in a text editor, like Notepad, and insert the following chunk of code between
the <form tag and the </form> tag:
<!--#include virtual="/cgi-bin/cotcha.cgi/print"-->
This will print the COTCHA code and an input box for returning the user's typed code.
Upload your changed form to your site.
ATTENTION: You might run into some problems here if your form doesn't have the .shtml extension,
and your server only allows included virtual tags in .shtml pages. There is a work-around, so contact
me for your options here. You'll know it's not working if the code is not inserted into the form
when it's loaded, yet it displays in your browser if you call the script directly.

5. This next part is a little harder. You need to open the Perl cgi script that is processing your
form, and modify it to test for the COTCHA. At the point where this script is about to
save or send its results, insert the following line:

require "cotcha.cgi"; &check_cotcha(param('cotcha'));

This causes the original script to open the cotcha.cgi script, and to check the value which the
user typed in.

Different guestbook and comment scripts process form submission in different ways. Sometimes a
form submission will be in the format $FROMWEB{'cotchta'}, or $WEB{'cotcha'}, or
$FORM{'cotcha'}, or some similar kind of thing. Inspect your original script to see how other
input is processed.

6. Somtimes you might need to have your existing script present the COTCHA code to the browser.
If this is your situation, then use the following line:

require "cotcha.cgi"; $cotcha = &return_cotcha_html_for_scripts;

This will make your existing script open cotcha.cgi, then set the variable $cotcha to be filled
with the HTML needed for your cotcha code. Within the print statements, simple type that
variable to have the HTML printed there-- remember, within the <form and </form> tags.

That's it! You're all set! If you have problems or questions, please don't hesitate to ask. You can also
get basic installation assistance from here:

Have fun!


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COTCHA $0.00
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 COTCHA is an acronym for Coded Objective to Tell Computers and Humans Apart. Similar to the CAPTCHA scheme, this script can be integrated into any pre-existing web form and/or perl script to add an extra element of spam protection.
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