PHP Classes

ASCII CAPTCHA: CAPTCHA validation using ASCII art text

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StarStarStar 55%Total: 4,203 This week: 1All time: 713 This week: 75Up
Version License PHP version Categories
ascii_captcha 1.0.0The PHP License3.0Text processing, Validation, Security


This class can be used to perform CAPTCHA validation, display text letters using ASCII art fonts.

It generates a CAPTCHA validation text string with random letters and then renders that text as an ASCII art string with multiple lines that represent the validation text with some distortion and noise characters.

The random validation text and the rendered text are returned as strings.

Innovation Award
PHP Programming Innovation award nominee
May 2008
Number 2
CAPTCHA validation is a way to make it more difficult the use of robot scripts to impersonate real users accessing sites.

Many techniques have been developed to implement different variants of CAPTCHA validation, but some can easily be defeated with more sophisticated robots.

This class provides different approach by using text rendered as ASCII art instead of using the usual obfuscated images. This way, existing CAPTCHA breaking robots would need to be adapted to bypass this solution.

Manuel Lemos
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Innovation award
Innovation award
Nominee: 4x

  Files folder image Files  
File Role Description
Accessible without login Plain text file documentation.html Doc. Documentation
Plain text file ascii_captcha.class.php Class The main ASCII CAPTCHA class
Accessible without login HTML file example.html Output Example code and output

 Version Control Unique User Downloads Download Rankings  
This week:1
All time:713
This week:75Up
User Ratings User Comments (3)
 All time
It's a simple class and it works.
12 years ago (michael)
Great :)
15 years ago (T. Schrammer)
There is a bug with counting the required number of backgroun...
15 years ago (Nikodem O.)