Secure Mobile App Development

I'm seeking an experienced mobile app developer to create a secure, encrypted vault application for both iOS and Android platforms. The app needs to be built with advanced encryption standards (AES-256) to ensure the highest level of security for user documents.

Key features include:
- Encrypted vault for document storage
- Will generation module
- Nominee management:
- Add/Edit/Remove nominees
- Set nominee permissions
- Notification to nominees upon changes
- Death-triggered access release system

Ideal candidates should have:
- Proven experience in developing secure mobile applications
- Expertise in implementing advanced encryption protocols
- Familiarity with iOS and Android development
- Strong understanding of user permission systems and notification mechanisms

Please provide examples of similar work done.