When the following is configured:
vyos@vyos# show interfaces wireless wireless wlan0 { channel 0 hw-id 04:c0:01:00:00:01 physical-device phy0 security { wpa { passphrase VyOS-WIFI-123 } } ssid VyOS-WIFI type access-point }
VyOS will have an "open" WIFI with SSID VyOS-WIFI. In order to protect the WiFi one must explicitly set: set interfaces wireless wlan0 security wpa mode <wpa|wpa2|both>
The default in VyOS 1.2 is "both"