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Module 4: Secure Data-Gateway API

Build a secure microservice for handling CRUD operations with AES-256-GCM encrypted JSON data storage. Learn to implement server-side encryption, create a minimal data gateway API, and protect sensitive data at rest outside the web root.

Module Objectives

Server-Side Encryption

Implement AES-256-GCM encryption for JSON data files stored outside the web root, ensuring sensitive information never reaches the client unencrypted.

Data-Gateway Microservice

Build a minimal Node.js or Python microservice that handles CRUD operations, encryption/decryption, and serves as a secure intermediary between your frontend and encrypted data.

RESTful API Design

Design and implement a clean RESTful API for Create, Read, Update, and Delete operations following industry-standard patterns and HTTP methods.

Security Architecture

Understand the security model where encryption keys stay server-side, data files live outside web root (/srv/webdesign_data/), and the gateway uses reverse proxy configuration.

Module Roadmap

Lessons

4 comprehensive lessons covering core concepts and hands-on implementation.

Start Lesson 1

Theory

Deep dive into theoretical concepts and industry best practices.

View Theory

Demo

Live demonstration of building a complete project from start to finish.

Watch Demo

Practice

Hands-on duplication assignment to reinforce your learning.

Start Assignment

Recommended Learning Path

Follow this sequence for optimal learning:

1. Lessons 2. Theory 3. Demo 4. Practice

Each step builds upon the previous one, so following this order will give you the best learning experience.

Prerequisites

Before starting this module, make sure you have:

  • Completion of Modules 1, 2, and 3
  • Understanding of JSON and API concepts
  • Basic knowledge of HTTP methods (GET, POST, PUT, DELETE)
  • Data-driven website from Module 3
  • Comfort with command-line operations

Key Technologies

Node.js or Python (microservice)
AES-256-GCM Encryption
RESTful API patterns
JSON file storage
Fetch API (client-side)
Reverse proxy concepts
Linux file permissions
Cursor IDE + Claude Code

What You'll Learn

By the end of Module 4, you'll have transformed your website from client-side data files to a secure backend architecture with encrypted storage. You'll understand encryption principles, secure API design, and be ready to polish your UI and deploy to production in the remaining modules.