QR Code Authentication

QR code authentication completes identity verification or login by scanning a QR code displayed on screen with a smartphone. It is used in LINE's PC login, WhatsApp Web, and various two-factor authentication apps.

Instead of entering passwords, scanning with an already-authenticated smartphone reduces password interception risks. However, watch for QRLJacking (QR login jacking): an attacker copies a legitimate service's login QR code onto a page of their own, gets the victim to scan it, and takes over the resulting session. This is distinct from QR code phishing, which steers the scan toward a fake URL; QRLJacking works even when the code points at the genuine service.