What is the Full Form of CAPTCHA?
CAPTCHA stands for “Completely Automated Public Turing test to tell Computers and Humans Apart.” It’s a type of challenge-response test used in computing to determine whether the user is human or not. This technology is used to prevent bots from accessing websites and automating tasks that should be performed by humans.
History of CAPTCHA
The history of CAPTCHA is a fascinating journey into the world of cybersecurity. The term was coined in 2003 by a team of computer scientists at Carnegie Mellon University, including Luis von Ahn, Manuel Blum, Nicholas J. Hopper, and John Langford. The concept, however, existed in various forms before this formal naming. CAPTCHA was created as a way to address the growing problem of automated bots on the internet, especially for the purposes of spamming or manipulating online services.
Various Types of CAPTCHA
Over the years, several types of CAPTCHA have been developed, including:
- Text-Based CAPTCHA: Displays distorted letters and numbers that users must type correctly.
- Image-Based CAPTCHA: Requires users to identify specific images from a selection.
- Audio CAPTCHA: Provides an audio recording of distorted text which the user must listen to and enter.
- ReCAPTCHA: A Google-developed system that asks users to perform tasks like identifying street signs or storefronts in images.
- Mathematical CAPTCHA: Requires users to solve a simple math problem.
Different Parts of the CAPTCHA Process
A CAPTCHA system typically involves:
- Challenge Generation: Creating a test that is easy for humans but hard for computers.
- Response Evaluation: Checking if the user’s answer is correct.
- Usability Consideration: Ensuring the test is accessible to all users, including those with disabilities.