What is the CAPTCHA feature used for on FortiGate devices?

The CAPTCHA feature on FortiGate devices is specifically designed to require human verification and prevent automated bots from accessing resources. This is crucial in protecting network security because automated bots can exploit vulnerabilities, attempt to access sensitive information, or perform actions that could disrupt service.

By implementing CAPTCHA, FortiGate ensures that only legitimate users can proceed to access certain resources, which significantly reduces the risk of automated attacks such as brute force attempts and spamming. It distinguishes humans from bots effectively, making it a valuable tool in safeguarding web applications and services.

While the other options mention various important network functions, they do not pertain to the specific role of CAPTCHA in a security context. For example, speeding up network traffic flow relates to optimization techniques rather than user verification, managing user authentication involves different methods such as passwords or tokens, and data encryption secures information during transmission, which again does not connect to the CAPTCHA functionality.