Every corporate WiFi network that prompts for a username and password rather than a passphrase is running 802.1X authentication backed by a RADIUS server. The mechanism is invisible to end users but structurally different from home WiFi in ways that matter enormously for security. Understanding how it works explains why enterprise networks handle compromised credentials, device theft, and regulatory compliance requirements in ways that passphrase-based networks cannot. The Limitation of PSK Authentication Home and small office WiFi uses a pre-shared key: one passphrase, shared among all users and all devices.