## Understanding CAPTCHA
CAPTCHA, which stands for Completely Automated Public Turing test to tell Computers and Humans Apart, is a security feature used to differentiate between human users and automated bots on websites and online platforms. This technology is designed to prevent spam, abuse, and unauthorized access by requiring users to complete a specific task or puzzle that is easy for humans to solve but difficult for bots.
### How CAPTCHA Works
When a user encounters a CAPTCHA, they are typically presented with a challenge that requires them to perform a specific action, such as typing distorted text, selecting images that match a certain criteria, or solving a simple math problem. These tasks are used to verify that the user is indeed a human and not a computer program attempting to exploit or gain unauthorized access to the system.
### Types of CAPTCHA
There are several types of CAPTCHA mechanisms that websites can implement to protect against bots. Some common types include:
1. **Text-based CAPTCHA:** Users are asked to type in distorted or obscured text displayed on the screen.
2. **Image-based CAPTCHA:** Users are required to select specific images that match a certain criteria, such as identifying all pictures with traffic lights.
3. **Checkbox CAPTCHA:** Users simply need to check a box to confirm that they are human.
4. **Math CAPTCHA:** Users are asked to solve a simple math problem, such as adding or subtracting two numbers.
5. **ReCAPTCHA:** A more advanced version