Page 204 - CITS - Computer Software Application -TT

COMPUTER SOFTWARE APPLICATION - CITS

Check if Cookies are Enabled
The following example creates a small script that checks whether cookies are enabled. First, try to create a test
cookie with the setcookie() function, then count the $_COOKIE array variable:
Example:

Captcha text generation

CAPTCHA Text Generation in PHP
Introduction:
CAPTCHA (Completely Automated Public Turing test to tell Computers and Humans Apart) is a security mechanism
designed to differentiate between human users and automated bots. Text-based CAPTCHAs involve generating
and validating distorted text that users must interpret and enter correctly to prove they are human.
Explanation:
The primary purpose of a text-based CAPTCHA is to prevent automated scripts from submitting forms on
websites, as bots often struggle to decipher and interpret distorted text. In PHP, CAPTCHAs can be implemented
by generating a random text string, displaying it as an image, and validating the entered text against the stored
value.
Implementation:
Let’s break down the steps to create a simple text-based CAPTCHA in PHP using the GD library:
1 Generate a Random Text String:

In this example, we use the `md5` function with the current timestamp to create a random string and store it in the
session variable ‘captcha.’

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CITS : IT&ITES - Computer Software Application - Lesson 47 - 62