Cross-Platform Mobile App for Coaching Institute

I'm looking for a talented mobile app developer to create a cross-platform (iOS and Android) application for my coaching institute. The app should have the following essential features:

- Online Live Classes: The app should support seamless streaming of live classes.
- File Sharing: A robust system for sharing class materials, assignments and other files.
- Student Progress Tracking: A feature to monitor and display students' progress over time.

The app also needs to incorporate user authentication, but the specifics depend on the feature. Therefore, the developer should have experience with secure login systems and data encryption.

Ideal Skills and Experience:
- Cross-platform mobile app development
- Experience in developing educational apps
- Strong knowledge in integrating live streaming capabilities
- Proficient in file sharing systems
- Able to implement and design progress tracking features
- Experience with user authentication systems
- Knowledge in data encryption and security measures.

Please provide examples of previous work that aligns with these requirements.