How to Build a Face ID-Secured File Encryption App for iPhone

Simple Summary

Build a secure File Encryption Tool for iPhone that uses Face ID for unlocking, providing users with an intuitive way to protect sensitive files.

Product Requirements Document (PRD)

Goals:

• Develop a secure file encryption tool for iPhone
• Implement Face ID authentication for unlocking encrypted files
• Create an intuitive user interface for file management and encryption
• Ensure high-level security standards are met

Target Audience:

• iPhone users concerned about data privacy and security
• Professionals handling sensitive information
• Individuals seeking to protect personal files

Key Features:

1. File and folder encryption
2. Face ID authentication for access
3. Secure file browser and management
4. Import/export functionality for encrypted files
5. Backup and restore options
6. Password recovery mechanism

User Requirements:

• Easy-to-use interface for file encryption and decryption
• Seamless Face ID integration for quick access
• Ability to organize and manage encrypted files within the app
• Option to share encrypted files securely
• Regular updates and security patches

User Flows

1. File Encryption:

   • User opens the app and authenticates with Face ID
   • Selects "Encrypt File" option
   • Chooses file(s) to encrypt from device storage
   • Confirms encryption
   • File is encrypted and stored in the app's secure storage

2. Accessing Encrypted Files:

   • User opens the app
   • Authenticates with Face ID
   • Browses encrypted files in the app's file manager
   • Selects a file to decrypt
   • Views or exports the decrypted file

3. Sharing Encrypted Files:

   • User selects an encrypted file
   • Chooses "Share" option
   • Selects sharing method (e.g., email, messaging app)
   • Optionally sets a password for the recipient
   • Sends the encrypted file

Technical Specifications

• Language: Swift for iOS development
• Encryption: AES-256 for file encryption
• Authentication: Face ID API integration
• File Management: FileManager for iOS
• Database: Core Data for local storage
• Networking: URLSession for any necessary API calls
• UI Framework: SwiftUI for modern, responsive interface
• Testing: XCTest for unit and UI testing
• Dependency Management: Swift Package Manager

API Endpoints

N/A - This app primarily operates locally on the device. However, if cloud backup is implemented in the future, consider endpoints such as:

• POST /api/backup: Upload encrypted backup
• GET /api/restore: Retrieve encrypted backup

Database Schema

Core Data Entities:

1. EncryptedFile

   • id: UUID
   • name: String
   • encryptedData: Binary Data
   • creationDate: Date
   • lastAccessDate: Date
   • fileType: String

2. UserSettings

   • id: UUID
   • lastBackupDate: Date
   • isCloudBackupEnabled: Boolean

File Structure

Implementation Plan

1. Project Setup (1-2 days)

   • Create Xcode project
   • Set up version control
   • Configure SwiftUI and project structure

2. Core Functionality (5-7 days)

   • Implement file encryption/decryption service
   • Create file management system
   • Develop Face ID authentication service

3. User Interface (4-5 days)

   • Design and implement main views
   • Create file browser and encryption UI
   • Implement settings and preferences UI

4. Data Persistence (2-3 days)

   • Set up Core Data for local storage
   • Implement file metadata management

5. Security Enhancements (3-4 days)

   • Implement secure key storage
   • Add password recovery mechanism
   • Perform security audit and optimizations

6. Testing and Refinement (4-5 days)

   • Write and run unit tests
   • Perform UI testing
   • Bug fixes and performance optimizations

7. Documentation and Submission Prep (2-3 days)

   • Write user documentation
   • Prepare App Store listing materials
   • Final review and submission to App Store

Deployment Strategy

1. TestFlight Beta Testing

   • Deploy to internal testers
   • Gather feedback and make necessary adjustments
   • Expand to external beta testers

2. App Store Submission

   • Prepare all required materials (screenshots, descriptions, etc.)
   • Submit for App Store review
   • Address any issues raised by the review team

3. Post-Launch

   • Monitor user feedback and ratings
   • Provide timely updates and bug fixes
   • Plan feature enhancements based on user requests

4. Marketing and Promotion

   • Create a landing page for the app
   • Engage with tech blogs and reviewers
   • Utilize social media for promotion

Design Rationale

• Swift and SwiftUI were chosen for native iOS development, ensuring optimal performance and integration with Face ID.
• AES-256 encryption is industry-standard and provides robust security for file protection.
• Core Data is used for efficient local storage and management of encrypted files.
• The file structure separates concerns, making the codebase modular and easier to maintain.
• Face ID integration provides a seamless and secure user experience, leveraging built-in iPhone security features.
• The implementation plan prioritizes core security features before moving to UI and refinement, ensuring a solid foundation for the app.