I am looking for an iOS email client that is reasonably secure (ideally, this means that it doesn't store user credentials outside the device - so something like Spark or Outlook for iOS are a no go for me).
I was thinking about the built-in Apple Mail.app but I couldn't find much about its security, so I have a few questions:
- Are my account usernames and passwords stored outside of my device at any time if I use this app?
- Is there any way to make sure (or to prove beyond reasonable doubt) that the creator of a mail app does not have access to the content of my emails?
- Bonus: does the situation improve if I disable push notifications?
I think this could be a useful discussion for those who are choosing their company's email client of choice and how to prove that one is or is not suitable for corporate use.
Note: this really only focuses on account credentials and email access, not on security in transit, which is already covered in this question.