We're trying to implement geofencing and it's fairly important that we're sure the user isn't using any location spoofing software or simply faking the request by not using our app.
We will be sending the location from our app as we get it from the device (iOS/Android) but we would also like to somehow ensure that the user is really at that location (or at least in the vincinity of it).
Since we will only be doing this in native apps on mobile devices the user will either be connected via WiFi or 3/4G.
Is it possible to (cryptograhpically?) verify that the user is connected to a specific cell tower or WiFi network/router without having access to said tower/router?