CAPTCHA stands for "Completely Automated Public Turing test to tell Computers and Humans Apart." It is a security measure used on websites and online platforms to distinguish between human users and automated bots.
The concept of CAPTCHA was first introduced in the late 1990s by researchers at Carnegie Mellon University to address the increasing concern of automated bots and scripts abusing online systems. The goal was to create a test that humans could easily pass but would be challenging for bots to solve.
The term "Turing test" refers to the famous test proposed by Alan Turing in 1950, which assesses a machine's ability to exhibit human-like intelligence. In the context of CAPTCHA, it involves presenting a task or challenge that requires human-level cognitive capabilities to solve correctly.
The use of CAPTCHAs has evolved over time, and different types have been developed, including image-based challenges where users need to identify specific objects or characters, audio challenges where users have to transcribe spoken words, and more advanced versions that use machine learning and AI to adapt and improve their effectiveness.
CAPTCHAs play a crucial role in preventing automated bots from engaging in activities such as spamming, brute-force attacks, data scraping, and other malicious actions that can harm websites and online services. They help ensure a better user experience, enhance security, and protect sensitive information from unauthorized access. As technology advances, so too does the ongoing effort to improve CAPTCHAs to stay ahead of increasingly sophisticated bots.