4.1 Introduction

In the previous chapter, we defined the architectural philosophy and layered structure of Offline Life Archive. We intentionally avoided writing feature-level code.

In this chapter, we begin implementation — but not at the UI layer.

Instead, we implement the secure infrastructure foundation, specifically:

• Encryption key generation and storage
• Encrypted Realm configuration
• Repository layer structure
• Service layer boundary enforcement

The goal of this chapter is to ensure that all future features operate on a secure and maintainable base.

4.2 Why Infrastructure Comes Before UI

In many projects, developers begin by building screens and connecting them directly to storage.

This approach introduces:

• Tight coupling between UI and data layer
• Refactor risk when database logic changes
• Security logic scattered across the codebase

Our architecture blueprint:

App Layer
Module Layer
Core Layer
Shared Layer
Data Layer

This chapter implements the Core and Data layers first.