This is clearly the best

It took a bit of work to get the keys in, I had to put in one key at a time through iTunes app section, but once they were in, I culd send email from the app. The app also lives in the share sheet so if someone sends a signed or encrypted, I and send the email from spoarrow to this app and have it verified and decypted. It would be amazing if Apple could to PGP on the native app, built in, but this is the next best thing. no more than 2 extra steps and it is quick.

Antiduplicity about iPGMail, v3.0.4