Secure Messaging App Development

I'm seeking an experienced developer to build a secure messaging app for both iOS and Android platforms. The app should include self-destructing messages with time-based deletion.

Key Features:
- End-to-end encryption
- Self-destructing messages (time-based deletion)
- Time intervals for deletion: 1 minute, 1 hour, 24 hours

Ideal Skills and Experience:
- Proficiency in mobile app development for iOS and Android
- Strong background in implementing encryption and security protocols
- Experience with self-destructing message functionalities
- Knowledge of user interface design for a seamless user experience

Please provide examples of similar projects you've completed and your approach to ensure security and privacy.