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?
This VoIP vs cellular doesn't have sense. Cellular networks are only link layer. They stablish low level telecom techniques to be able to transport any data to a cellular mobile belonging to the cellular net. The main difference with other link layer aproaches like wifi, ethernet, bluetooth, etc. Is that terminals are linked to a net of base stations in order to keep the best connection to the net at all times from every posible place. In order to do that each base station needs to know which terminals (phone numbers) are in his vicinity and in which sector. This way the cellular network knows where to look for when searching for a given terminal.
VoIP is an application layer service. Which means you can use VoIP over link layers like bluetooth, wifi, ethernet, cellular network. There's no VoIP vs cellular network. Cellular network can carry VoIP data because cellular network can carry IP datagrams. All modern cellular network use VoIP as their way to carry the voice information over the net and to maintain connection.
Wifi calling vs VoIP also makes no sense. You can do VoIP on wifi. Wifi is a link layer it can carry any digital data encapsulated.
What I understand you are saying is using VoIP through Wifi instead of using VoIP over cellular network.
In order to help a bit more, this are some.VoIP services:
Discord. Linephone Skype. Mumble.
I've used wi-fi calling fairly extensively mostly because I've lived in areas where there was zero cell service but ready access to internet (via Starlink or other wireless forms of it). One thing I do know is that my phone co. requests that I fill out a form specifying where I am living currently (whilst using it) so that if I ever need to contact emergency services they'll have a better idea of where to route the call to. For instance my phone number originates from Western BC but I could potentially be using wi-fi calling from anywhere in the province. I mention this to say, it appears my telco doesn't have a way to triangulate me with this service.
I can further attest that wi-fi call & text reception still works fine when I have a VPN running on the router that my mobile device is connecting to. Make of that information what you wish.
Though that I have read that wi-fi calling is atrocious for privacy reasons that I have not followed up on. Given the above I'm not sure how or why that would be the case, but basically if I'm in an area with cell coverage I turn it off. I've always meant to look deeper into how or why it might be bad (or worse) in some way.
If I'm understanding how 'WiFi Calling" works; it's still "identifying you" to the cell provider the same way; via your SIM. The only difference is they don't get an exact location because you're not using any cell towers typically.
I do suspect SIMs and eSIMs are still doing all the heavy cryptographic signing done on a typical phone network though...they're just not screaming your IMEI/IMSI all over open or even encrypted airwaves; nor is a WiFI signal triangulate-able typically due to it's short range.
I don't know what kinds of packets WiFi calling sends, but I would assume a public IP would be in there somewhere and, at least from a law enforcement perspective I can't imagine it would be too hard to get the address tied to it.
I strongly suggest you look into jmp.chat. That's what I've been using exclusively for the last 3 months , no problem. When I'm out, I just carry a prepaid 5G mobile modem with me, and have yet to miss a single call or sms (as far as I know). I haven't missed being attached to a mobile provider in the least. And since my mobile modem is unlocked and prepaid, I can just throw away the Sim if I don't want to use them anymore and use some other provider. Nevermind the huge savings since I moved to this flow.
Are you aware that using the same device with different SIMs is not helping your anonymity because IMEI is the same?
Power to you for not having GSM enabled on your phone though
Oh, I know. The reason for switching Sims is because they do something I don't like, not for anonymity or even privacy. But it's good that you mention it here.
I used an iPod touch for calling over WiFi for years. It worked just fine, as long as one had a WiFi connection. Do it!
Is WiFi calling a decent alternative to VoIP?
I've placed calls using WiFi calling where the person said they could barely understand the words I was saying due to sound distortion. When I called back over VoIP, they said it was crystal-clear.
