I've never output a form that prompted the user to enter the characters represented in a Captcha image. But if you had a table on your server that cross-referenced the character representation with the image file name, the validation logic would just be a regular string comparison against the appropriate table row & column, and the type of thing you could easily do in just about any server language.
I understand that the purpose of distorting the image is to prevent it from being converted to a character string via standard optical character recognition, which could be employed via bot. You want to make sure the user is more intelligent (human) than a bot.
So my question would be, is there software available that can convert simple character strings into distorted image representation, so you can generate your own table of prompts?
Nathan.
----- Original Message ----
From: "Guillermo Andrades, CPI Software" <gab@xxxxxxx>
To: Web Enabling the AS400 / iSeries <web400@xxxxxxxxxxxx>
Sent: Sunday, August 31, 2008 1:39:47 PM
Subject: [WEB400] CAPTCHA image validation in web form
some experiences using captcha image validation in web forms?
please not php not python not java....
(btw, info about captcha in wikipedia:
http://en.wikipedia.org/wiki/Captcha)
Interested in some way of web services or having a full directory with
images or so on, some not requering script in the host (RPG code, even C or
C++ will be welcome).
The intend use is an not-as-secure-as-FBI form, thus: don't need double nor
complex validation.
client side is html+javascript, host is RPGIV.
Thanks in advance,
Guillermo.
midrange.com
