Add Device Identity and Registration System Using Ed25519 and TCP with Persistent Device Identity Support

[ShigrafS]

🧾 Summary

This PR introduces a new device registration system by replacing the existing tcp_server.py implementation with a modular architecture consisting of:

• identity.py: Generates and persists a unique device identity and public key.
• register_client.py: Handles client-side registration to the central registry server.
• registry_server.py: Central registry server to assign unique 3-digit IDs and store device metadata.

The change adds 133 lines of new code and removes 126 lines by removing the monolithic tcp_server.py.

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📂 Changes Overview

✅ Added:

1. identity.py

   • Generates Ed25519 key pairs for the device.
   • Persists private keys in device_key.pem.
   • Returns a unique device_id (first 20 chars of SHA-256 hash of the public key) and the PEM-encoded public key.

2. register_client.py

   • Calls get_device_id_and_key() from identity.py.
   • Sends device info (device_id, public key, IP, port) to a registry server over TCP.
   • Displays the server's response after registration.

3. registry_server.py

   • Listens on port 9000 for incoming client registrations.
   • Assigns a unique 3-digit number (starting from 100) to each device.
   • Stores device data (ID, public key, IP, port) in a local JSON file db.json.
   • Returns a JSON response to the client with registration status and number.

❌ Removed:

• tcp_server.py

  • Removed in favor of the new, modular, and more maintainable system.

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🎯 Motivation

The previous tcp_server.py lacked modularity, device identity persistence, and proper state tracking for registered clients.

This PR addresses those issues by:

• Separating concerns (identity generation, client logic, server logic).
• Introducing persistent identities and registry.
• Improving maintainability, extensibility, and clarity of the registration process.

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⚠️ Potential Issues / Considerations

• Key Persistence: Currently stores private key in plain PEM format — consider encrypting it for production.
• Concurrency: registry_server.py uses basic threads; future improvements might involve async I/O or thread pooling for scalability.
• Security: Registration over raw TCP lacks authentication and encryption — may need TLS and device signature verification.

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🧪 How to Test

1. Run the registry server:

   python registry_server.py

2. Register a client device:

   python register_client.py

3. Expected Behavior:

   • Client prints registration response with assigned number.
   • Server updates db.json with new device metadata.
   • device_key.pem is created on first run and reused thereafter.

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📌 Related Tickets / References

• Replaces outdated tcp_server.py
• Lays groundwork for future features like secure communication and authentication.