Access Point

An access point (AP) is the device that serves as the connection hub of a Wi-Fi network. Access points are installed everywhere wireless LAN is offered — home routers, free Wi-Fi in cafes, corporate office networks. Smartphones and laptops connect by detecting the SSID (network name) that the access point broadcasts.

The relationship between QR codes and access points comes down to one thing: simplifying the act of joining a Wi-Fi network. Traditionally a user had to select the SSID and type the password by hand. A Wi-Fi QR code stores the SSID, the password and the encryption type (WPA2/WPA3) in the format WIFI:T:WPA;S:NetworkName;P:Password;;, so a single scan is enough to connect automatically.

Wherever Wi-Fi is offered to guests — hotels, cafes, coworking spaces, event venues — the QR code has become the standard means of handing it over. Simply displaying a code at the front desk or on the table removes the chore of reading out a complicated password or writing it on a slip of paper.

One security caveat: a Wi-Fi QR code displayed in a public place can be swapped for a fake. The attack works by embedding the credentials of a rogue access point (an Evil Twin) in the code, then intercepting the traffic of everyone who connects. The recommended practice is to scan only codes displayed in places you trust, and to use a VPN once connected.