How to check if listed Wi-Fi signal is secured?

Question

Can I check if a boradcasting SSID is secured with a key, without attempting to connect to it?

Answer 1

Using WifiManager's getScanResults method, and check ScanResult's capabilities field value.

    WifiManager wm = (WifiManager) getSystemService(Context.WIFI_SERVICE);
    wm.startScan();

    //some time after...

    List<ScanResult> results = wm.getScanResults();
    for( ScanResult result : results ){
        //if this ap is locked, the capabilities string should contains..
        //the name of encryption mechanism. ex> [WPA2-EAP-CCMP]
        Log.v("AP", "AP:" + result.capabilities);
    }

In my case, the result log looks like this...

09-16 21:01:41.308  V/AP﹕ AP:[WPA-EAP-CCMP+TKIP][WPA2-EAP-CCMP+TKIP][ESS]
09-16 21:01:41.308  V/AP﹕ AP:[WPA-PSK-CCMP][WPS][ESS]
09-16 21:01:41.308  V/AP﹕ AP:[WPA2-EAP-CCMP][ESS]
09-16 21:01:41.308  V/AP﹕ AP:[WPA-PSK-CCMP][WPA2-PSK-CCMP][WPS][ESS]
09-16 21:01:41.308  V/AP﹕ AP:[WPA2-EAP-CCMP][ESS]
09-16 21:01:41.308  V/AP﹕ AP:[WPA2-EAP-CCMP][ESS]

You may need below permissions in order to scan & read result.

<uses-permission android:name="android.permission.ACCESS_WIFI_STATE"/>
<uses-permission android:name="android.permission.CHANGE_WIFI_STATE"/>