U2FREGISTER
U2FREGISTER is a JavaScript function used in web applications to facilitate the registration of FIDO U2F (Universal 2nd Factor) security keys. When a user wishes to add a new U2F device to their account, the web application calls this function. U2FREGISTER communicates with the browser, which in turn interacts with the connected U2F security key. This process involves the security key generating a unique cryptographic key pair for that specific website and user. The public key is then returned to the web application and stored as part of the user's authentication credentials. The private key remains securely on the U2F device and is never exposed. This enables strong, phishing-resistant two-factor authentication. U2FREGISTER is a crucial component of the FIDO U2F JavaScript API, which aims to standardize and simplify the implementation of hardware-based second-factor authentication for web services. Its use is integral to providing a more secure login experience by moving beyond less secure methods like SMS-based codes.