The full form of "CAPTCHA" is "Completely Automated Public Turing test to tell Computers and Humans Apart."
CAPTCHA is a security measure used on websites and online services to distinguish between human users and automated bots. It was first introduced in the late 1990s by researchers at Carnegie Mellon University to address the problem of automated bots spamming and abusing online platforms.
The purpose of CAPTCHA is to present challenges or puzzles that are easy for humans to solve but difficult for automated bots. By doing so, it helps prevent malicious bots from accessing sensitive information, creating fake accounts, submitting spam, or engaging in other undesirable activities.
CAPTCHAs come in various forms, such as distorted text, image recognition, checkbox verification, puzzle-solving, or even audio challenges for visually impaired users. Over time, CAPTCHA techniques have evolved to be more user-friendly while maintaining their effectiveness in thwarting bots.
By using CAPTCHAs, websites can enhance their security, protect user data, and improve the overall user experience by reducing spam and unwanted automated actions.