I mean, people say use end to end encryption, VPN, Tor, Open Source Operating System, but I think one thing missed is the hardware is not really open source, and theres no practical open source alternative for hardware. There’s Intel ME, AMD PSP, so there’s probably one in phones. How can people be so confident these encryption is gonna stop intelligence agencies?
Every phone has a radio with remote root access controlled by a security key that is supposedly only in the hands of the manufacturer. A manufacturer that could be forced to give up that key, and forced not to tell anyone they had done so.
At least with a PC you can control the physical access to transmission, giving you a way to possibly audit before send, and physically control all input.
The reality is that any large scale communication network will be breached by the controlling government, or it will be shut down. If you want actually secure communication, you have to do it by broadcasting in the clear using an unbreakable cypher that’s been physically passed on.