Android + information protection. Suggest topics for the thesis

Question

Java

I am finishing my studies at the university with a degree in Integrated Information Security of Automated Systems. Need a theme for the thesis - an application that will affect the topic of security (in) OS Android.
In the last coursework, I implemented, roughly speaking, a phone book with a blocked entry.

Answer 1

The most obvious thing is to add encryption to this phone book ...
A kind of "safe"

Answer 2

Write "piracy protection". Well, or conduct a possible overview of the techniques with which you can protect the application from illegal distribution. And then a post on Habr, I would read it.