If you want to protect against an adversarial Google, you shouldn't be using Gmail at all. If you want to protect against an adversarial nation-state, well, po

If you want to protect against an adversarial Google, you shouldn't be using Gmail at all. If you want to protect against an adversarial nation-state, well, power to you, but it's an uphill battle. Use PGP, not S/MIME, and pray that everyone else knows how to use it perfectly, making no mistakes at any point ever.