Using Tor onion services that get exchanges when adding a contact nearby via WiFi or Bluetooth. If adding over the internet, a rendezvous service will be created.
If you have to stay on the Internet, my research indicates that the short term safety from surveillance, to the degree that is even possible, is to use a service like Kolab for email, which is located in Switzerland, and hence is under different laws than the US, laws which attempt to afford more privacy to citizens. I have now gotten for myself an email there, p.jones at mykolab.com in case anyone wishes to contact me over something really important and feels squeamish about writing to an email address on a server in the US.
If you have to stay on the Internet, my research indicates that the short term safety from surveillance, to the degree that is even possible, is to use a service like Kolab for email, which is located in Switzerland, and hence is under different laws than the US, laws which attempt to afford more privacy to citizens. I have now gotten for myself an email there, p.jones at mykolab.com in case anyone wishes to contact me over something really important and feels squeamish about writing to an email address on a server in the US.
And you probably should, if you want to maximize your legal protections against governments where third-party access to your data gives the government easier access to your data.
At least it is Free Software with reproducible builds, so you can audit the shit out of it.