How to send S/MIME encrypted mails from iOS with attachment? I can only send encrypted mails if I start the mail app directly. But if I try to send a mail from the image gallery, the mails are neither signed nor encrypted (and I can't find a way to enable that).

Edit: My current (non-acceptable) workaround would be to save the mail as a draft, then open the draft with the default mail app and then send it.
I can tell you why this happens but not give you a solution. To me this is a bug, when you 'mail' from within photos or whatever other app, using the modal compose window (the one that pops up from the bottom of the screen) you are using a MFMailComposeViewController class, this is effectively a baby version of mail that pops up and composes mail for you, then redirects this to the mail app.

Something is broken in between that's causing your issue.

Bottom line the MFMailComposeViewController (https://developer.apple.com/library/ios/documentation/MessageUI/Reference/MFMailComposeViewController_class/Reference/Reference.html) is not the full mail client and thus it's lacking the encryption piece.