Use GPG! Duh!

USE-GPG!

This page used to advertise the use of encryption even with casual email conversations. After Snowden, though, I don't think the point I wanted to bring across needs anymore advertisement. If you still think it's unnecessary to protect your private communication, I can't help you. I don't think anyone could.

Anyway. GPG is still Free and Open Source Software, and is available on virtually every platform.

You should use it.