Cross-Platform Secure Messaging App Development

I'm looking for an experienced developer to build a secure messaging app for both iOS and Android platforms. The app should include:

- Text Messaging: User-friendly, reliable text messaging functionality, local database, confirming tool, and sync as my requirements.
- End-to-End Encryption: Ensure all messages are protected with robust encryption.

Requirements:
- Experience in building messaging apps
- Strong knowledge of encryption technologies
- Proficiency in mobile app development for both iOS and Android

Please provide samples of similar work done.