One of the factors I considered was, having all the text encrypted and stored in the device memory. But we cannot avoid having raw unencrypted data on the RAM, when the application runs. Won't Antivirus, and other system level processes have access to the contents in my application's memory? Is there a way to ensure that the app's runtime memory is not viewed or monitored by another application?
I want this application to work well on Samsung Galaxy on8 that runs Android 8.0.
The purpose of this is, I want to be able to store notes/data that I don't want even the phone manufacturers or Google (through the OS) to have access to its contents. I do understand that people with a requirement of security at this level, will have a custom built hardware. But I just want to create a super secure application as a project.