Comment by John_KZ
8 years ago
There's no way to do this without using your own antenna network. Even then, you need encryption just to anonymize your calls, but if you end up talking to people subscribed to the same carriers you're trying to avoid, you can trivially be de-anonymized by timing attacks. So there's no good solution, unless you're willing to turn your calls to voice mail.
More practical solutions would include:
-(physically) Powered off radio unless you want to make a call. A clear drawback is that you can't receive calls.
-Satphones. I'm pretty sure satellite phone providers aren't in this yet. They could be, but my guess is that they wouldn't want to waste bandwidth triangulating their users. Also satellite-based triangulation would be much harder and less accurate, and if you use your own directional antenna and sat-tracking mount, you can avoid this altogether. Until they start installing phased array antennas or something.
-Finding a provider that doesn't sell your data to third parties. Probably the hardest of all, and you have to rely on their word.
It used to be possible to buy prepaid SIM cards with cash and not have to provide any identification. AFAIK, this isn't possible anymore. Does anyone know for sure?
The providers in our country require ID. I think there was an EU directive in 2006 that gradually forced all providers to require identification. Of course this doesn't stop criminals in the slightest, they just get second hand SIMs registered by homeless or just SIMs from outside the EU, so it was a pointless law with regards to reducing crime, but if the goal was more surveillance they did ok.
Laws are everywhere to prevent this, because without ID, a terrorist can buy a SIM card and put it in his GSM-controlled IED. Not sure how strong it is being enforced though, the terrorist can just give a homeless guy a few bucks to buy a SIM card for him. IIRC when I bought a SIM card in an Asian country I went to visit, the seller just entered her ID number into the system.
The real question being: How hard is it to bypass/cheat the identification requirement? Especially considering the US doesn't even have something like an official ID card.
They also changed this in Germany. Now you have to fill out a form to activate your SIM, but afaik nobody ever checks if the information in the form is actually yours.