🚀 P2P-Sharing-Application

A high-performance peer-to-peer file-sharing application designed for secure, direct data exchange.

🏗️ Architecture & Stack

• Frontend: Flutter (WebRTC / RTCDataChannel)
• Signaling Server: Spring Boot (WebSockets) -> Moving to Go for high concurrency!
• STUN Server: Standard Java (Custom UDP Implementation)
• Protocol: WebRTC (SCTP over UDP)

🔄 The P2P Handshake Process

1. Room Creation: Sender initiates a WebSocket connection to the signaling server.
2. Joining: Receiver joins via a unique RoomID.
3. SDP Exchange:
   • Sender generates Offer (SDP).
   • Receiver processes Offer and generates Answer (SDP).
4. ICE Gathering (Parallel): Both peers query the Java STUN Server to discover their public IP/Port.
5. Candidate Exchange: Peers relay their ICE Candidates via the signaling server.
6. Direct Connection: Once a path is found, a direct RTCDataChannel is opened, and file transfer begins—bypassing the servers entirely.

🚀 Key Features

• Zero-Server Storage: Files never touch the server; they move directly from phone to phone.
• Custom STUN: Optimized reflection logic built from scratch in Java.
• Async Messaging: Non-blocking signaling flow for fast room negotiation.