Protocol

A protocol defines the procedures, formats, and rules for data exchange between devices. HTTP, HTTPS, FTP, SMTP, Bluetooth, and Wi-Fi are protocols for different purposes.

The URI scheme in QR code data specifies the protocol: https:// for web access, mailto: for email, tel: for phone calls. Smartphones parse the scheme and launch the corresponding application.

Protocol choice directly affects security. HTTPS (TLS-encrypted) instead of HTTP protects post-scan communication. Chrome warns about unprotected HTTP sites, increasing bounce rates from QR code links.

Wi-Fi QR codes must specify security protocols (WPA2, WPA3). The deprecated WEP protocol has known vulnerabilities and should never be used in Wi-Fi QR codes.