Need a freelancer for development authentication features using AOSP

We are looking for top notch Android developer to lead and develop extra authentication layer for existing email application installed on secured and hardened mobile phones. OS - KitKat

Experience in development mobile authorization or authentication features in Android.
Experience in developing APKs/SDKs or low level Android development - expert level is must
Background in cyber - big plus
C++ experience - big advantage

This project requires 20-40 monthly hours availability for then next 2-3 months.