Mechanism behind QR code scanning of whatsapp webapp

Question

• I could not find any answers related to the working mechanism of qr code scanning used on whatsapp web-app.
• How does the authentication happen when th

Answer 1

It uses something like below.

1. Whatsapp web application is opened by user via web browser.
2. Server creates a UNIQUE token (number) and embeds that number in QR-Code
3. Whatsapp phone application reads QR-Code and decodes token.
4. Whatsapp phone application sends information about its current user and this newly read token to whatsapp server.
5. Whatsapp server matches token (+ phone app user information) with web browser.
6. It automatically authenticates user and open new web page with his/her information on it.