How do Authenticator apps work offline? 📱 The magic is TOTP (Time-based One-Time Password)! It relies on two things: 1. Secret Key (from the setup QR code) 2. Unix Time Your app divides the current time by 30, combines it with the Secret Key, and uses an HMAC-SHA1 hash to generate a 6-digit code. The server does the exact same math! Since no data exchange is needed, it's completely immune to SIM swapping. No physical phone, no login. Did you know about this offline magic? 👇