Up until recently, it was a pain to defend againt WPA2 brute-force attacks by using a random 63-character password (the maximum in WPA-Personal) mode). Thanks to Android 10 and iOS 11 supporting reading WiFi passwords from a QR code, this is finally a practical defense.

Generating the QR code

After installing the qrencode package, run the following:

qrencode -o wifi.png "WIFI:T:WPA;S:<SSID>;P:<PASSWORD>;;"

substituting <SSID> for the name of your WiFi network and <PASSWORD> for the 63-character password you hopefully generated with pwgen -s 63 .

If your password includes a semicolon, then escape it like this:

"WIFI:T:WPA;S:<SSID>;P:pass\:word;;"

since iOS won't support the following (which works fine on Android):

'WIFI:T:WPA;S:<SSID>;P:"pass:word";;'

The only other pitfall I ran into is that if you include a trailing newline character (for example piping echo "..." into qrencode as opposed to echo -n "..." ) then it will fail on both iOS and Android.

Scanning the QR code

On iOS, simply open the camera app and scan the QR code to bring up a notification which allows you to connect to the WiFi network:

On Android, go into the WiFi settings and tap on the WiFi network you want to join:

then click the QR icon in the password field and scan the code:

In-browser alternative

If you can't do this locally for some reason, there is also an in-browser QR code generator with source code available.