I am looking into mail kit extensions and I can see that a security handler extension is the recommended way to offer encryption functionality for emails, however if user chooses to click the padlock icon in top right side of compose window, he can opt out of encryption and the security handler encode method is not called. Is there a way to force and mandate that user cannot opt out of encryption and a security handler's encode method is always called by Mail?
My objective is actually to be able to inspect every mail attachment and depending on my business logic, I want to encrypt some of the mail attachments. So I need to make sure my security handler's encode method is called, always. Any other approach for achieving the same is also welcome.
