I've been using GrapheneOS as my main mobile phone for years, and recently without a SIM card. It's been great for most of my needs, but I've realized that having a local phone number is essential for certain situations where I need to make or receive regular phone calls. To address this issue, I'm thinking about buying a dumb/basic/feature phone only for this purpose.
But, before making any moves, I wanted to get some additional thoughts on potential privacy and security implications associated with this approach. Considering my higher-than-average threat-level and the involvement of a government adversary, I want to be as cautious as reasonably possible.
I'm aware that regular phone calls and SMS are fundamentally insecure, and I would only use it if it's truly necessary. I am also aware of the government being able to listen and record the conversations, and to locate the phone via cell-tower triangulation. My primary concern would be:
- Is it technically feasible for government agencies to "hack" into a standard, basic mobile phone and activate its microphone and camera?
- If so, are there any steps I can take to mitigate this risk (beside covering its camera and purposefully ruining its microphone, and then using an external one when needed), like using a specific type of feature phone or a particular phone plan, or something else...?
Any suggestions, insights and ideas would be highly appreciated!