A lot of apps want access to my email (and to my file system). I don't want to give it to them, but on KitKat, my only option is to uninstall or not install the app in the first place.
(I will ask separate questions about other apps with sensitive data.)
If there was an alternative app which I could use for email which would keep its local data encrypted - even when the phone is unlocked and in use (and maybe even when the alternative app is using the data), then I could install whatever I want because other apps couldn't decrypt anything I care about - even if they went directly to the file system.
Since my email is IMAP, there would also have to be something to keep the apps from skipping the local copies and going directly to the server(s).
Does anything like this exist?
A lot of people could use an app like this.
I'd like a generally applicable answer, so the information below shouldn't be used to rule out solutions that might work on another device or version of Android.
I do know that, starting with Marshmallow, you can restrict apps from having specific permissions, but not having Marshmallow, I have no experience as to how practical that actually is - if the apps keep working, etc..
If it makes a difference, I currently have a Galaxy S3 running KitKat, but am looking to upgrade soon. My phone is not rooted.
The mail I care about is not on gmail. It's on a small ISP's server accessed using IMAP. I think I currently have the default mail app set to save local copies of my emails, but I can't find the setting at the moment.
(My other computer (notebook) runs Linux where I don't have problems like this, but it won't fit in my pocket or act as a "normal" phone.)