How Authenticator Apps Generate the Same OTP on Authenticator APP as Your Server Without Any Communication between them One of the most common questions developers ask when learning Multi-Factor Authentication (MFA) is: How does my server generate the exact same OTP as an authenticator app like Google Authenticator without sending anything to it? At first, this seems confusing. You might assume one of these things happens: The server sends the OTP to the authenticator app The authenticato...