Is it even possible on android? Is there a FOSS dialer to optionally encrypt some phone calls (non voip) using a pre-shared key with other party?
Is it even possible on android? Is there a FOSS dialer to optionally encrypt some phone calls (non voip) using a pre-shared key with other party?
OP doesn’t say where they are, but at least in the US, there is no more such a thing as the “cellular network” like the old circuit-based analog systems or 2G/3G, practically everything is VoIP now. All carriers are requiring VoLTE at a minimum which is IP-based (and so is everything that will come after it). So to me, using a different app like Signal is not going to be a huge difference in quality as long as the codec being used is a similar bitrate to what VoLTE uses (AMR-WB I think at a minimum).
Agreed. It’s a fun thought experiment. You have an acoustic tunnel. It may be transited over VoIP it may not. You can use that acoustic tunnel however you like, so implementing secure voice via audio is doable even if the underlying network turns it into VoIP
For what it’s worth signal voice quality is much much much much much much much higher, because it can use more bandwidth, then cellular voice connections