ClipSync

LAN clipboard synchronization for Windows — encrypted, instant, zero-config.

Copy on one machine, paste on another. No cloud, no accounts, no internet required.

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Features

• Instant clipboard sync — Sub-50ms latency over LAN
• AES-256-GCM encrypted transport — All traffic encrypted using a shared secret
• Auto-discovery via UDP broadcast — Peers find each other automatically
• System tray integration — Runs silently in the background
• Zero workflow changes — Ctrl+C and Ctrl+V work exactly as before
• Self-contained installer — No .NET or dependencies needed
• Dark aesthetic UI — Modern dark theme interface
• Challenge-response authentication — HMAC-SHA256 mutual auth
• Automatic reconnection — Exponential backoff with infinite retry
• Heartbeat monitoring — Detects dead connections proactively

Download

Download the latest .msi installer from the Releases page. Just install and run — no additional downloads or setup required.

How It Works

Windows Clipboard → ClipboardMonitor → SyncEngine → AES-256 Encrypt → TCP → Peer

1. Install ClipSync on both machines (same LAN)
2. Set the same shared secret on both
3. Peers auto-discover each other via UDP broadcast
4. Copy text on one machine → instantly available on the other

Architecture

Component	Responsibility
ClipboardMonitor	Win32 WM_CLIPBOARDUPDATE listener
SyncEngine	Orchestration, dedup, loop prevention, auth
TransportLayer	Persistent TCP + AES-256-GCM + length-prefixed framing
DiscoveryService	UDP broadcast auto-discovery
AuthenticationService	HMAC-SHA256 challenge-response

Tech Stack

• .NET 9 (Windows, self-contained)
• WPF (Dark theme)
• Raw TCP sockets
• AES-256-GCM encryption
• Serilog structured logging
• xUnit + FluentAssertions (127 tests)
• WiX Toolset (MSI installer)

Building from Source

Prerequisites

• Windows 10/11
• .NET 9 SDK

Build

dotnet build src/ClipSync.sln

Run

dotnet run --project src/ClipSync.App

Test

dotnet test src/ClipSync.sln

Publish (self-contained)

dotnet publish src/ClipSync.App -c Release -r win-x64 --self-contained true -p:PublishSingleFile=true

Configuration

Settings stored at %LOCALAPPDATA%\ClipSync\settings.json:

Setting	Default	Description
listenPort	5000	TCP port for clipboard sync
discoveryPort	5001	UDP port for auto-discovery
sharedSecret	(auto-generated)	Key for encryption & auth
autoConnect	true	Auto-connect to discovered peers
startWithWindows	false	Launch at Windows startup
startMinimized	false	Start minimized to tray

Both peers must use the same sharedSecret to connect.

Security

• AES-256-GCM encryption on all clipboard data
• Key derived via PBKDF2-SHA256 (100,000 iterations)
• HMAC-SHA256 challenge-response authentication
• Constant-time comparison (prevents timing attacks)
• Unique random nonce per message
• GCM auth tag prevents tampering

Project Structure

src/
├── ClipSync.Core/          # Domain models, interfaces, crypto, serialization
├── ClipSync.App/           # WPF application, services, dark UI
├── ClipSync.Tests/         # 127 unit, integration & performance tests
└── installer/              # WiX MSI installer definition

License

MIT License — Copyright © 2024-2026 Manas Choksi

Author

Developed by Manas Choksi

• GitHub: @choksi2212
• Repository: clip-sync