I'm investigating getting off the cell network permanently to avoid at least the constant triangulation of my position. I figured I'd look into getting a VoIP number and getting calls and texts over WiFi. I don't mind being unreachable when I'm not connected to a hotspot, so it's not a problem for me.
But before looking for a good VoIP provider, I decided to check if WiFi still worked in airplane mode. And indeed it works. But to my surprise, when I connected the WiFi, my cellphone provider's name also came right back up at the top right of the screen. In airplane mode? What the hell?
Long story short, after investigating a bit, I realized I had WiFi calling enabled. So I can in fact already get calls and texts without being on the cell network.
And I'm thinking, maybe that's good enough for privacy?
I mean I know SIMs leak information like ICCID / IMSI / IMEI so obviously they have no reason not to do that over WiFi also and that's not so hot.
But on the plus side, none of that information is linked to cell towers and location anymore - at least not precise location if I'm not on a VPN - the baseband processor is off and can't do whatever shady chit-chat it does with the SIM and the cell towers, and I can still use my normal phone numbers without having to change and tell a million people that I have new numbers if I go with VoIP.
Also, I don't store my contacts on my SIMs and I use a deGoogled Android. So I figure that limits how much adversarial software can exploit the SIMs to leak data.
So it seems to me that WiFi calling may be a good solution for me for better privacy without too many compromises.
Can you think of something I missed that I should know before using this feature?
Using things like Signal and WhatsApp may reduce your footprint further.
I’ve used wifi calling from hotel rooms overseas as well as locations where mobile coverage is poor and it works fine. I suspect (not know) that the voice network provider knows pretty much where your location is though.
I use Signal with most of my family and friends. The phone things is for random people or companies that need to call me, and the texts are mostly to get notification when I receive a parcel, or confirmations for appointments, that kind of things.
WhatsApp, being owned by Facebook, can fuck right off.
Totally agree about WhatsApp as I no longer use it due FB shenanigans. A lot of people do though which is interesting as it so easy to move.
For texts with parcels etc I have an old phone in a drawer which forwards texts to my email. Doesn't leak anything because it does not move.
What software do you use to forward the texts automatically?
Actually I kind of had the same idea but for the whole phone - i.e. leave a cellphone with phone features at home (so voice and texts are received on this static phone that never gets used for anything else) and forward calls and texts on another cellphone with data only. But I don't think there's anything to set that up easily.
I wrote something myself because I wanted PGP support, but saw some apps on Google Play (I've been still using it back then). I can't recommend anything, sorry.
For calls - yeah, tough stuff. I'e been looking to do the same thing you did, and found there are GSM USB dongles (modems) that can work with Asterisk to forward calls, so you'd use a raspberry pi instead of a smartphone. But I never implemented it, people gradually stopped calling me and there was just no motivation.