WebRTC allows for real-time communication through a web browser or mobile app using audio, video, and data without requiring a centralized server. It works by using STUN and TURN servers to handle signaling and traverse NATs to establish a direct peer-to-peer connection when possible. WebRTC implements encryption and permissions to help secure access to devices and media streams, though vulnerabilities still exist around stolen credentials and unverified certificates. It supports advanced features like simulcast for adaptive streaming and SFUs for flexible multi-party video routing.