Use a third party tool instead of putting all your trust into a single point of failure. There are plenty to choose from. What you're proposing is pretty compl

Use a third party tool instead of putting all your trust into a single point of failure. There are plenty to choose from. What you're proposing is pretty complex and time consuming, you can't expect the average user of this extension to do that (I know I wouldn't). Or alternatively decide that you're fine with trusting google with whatever info is in your emails because you believe they have to much to lose if they're caught eavesdropping on some random Joe like me. That's what I do. And if tomorrow I feel I have a mail sensitive enough that I don't want to risk Google or some government intercepting it I certainly won't do it from my web browser's using Google's own extension.