ZeroRank

A trustless, privacy-preserving web application for anonymous ranking. Built on Multi-Party Computation (MPC), ZeroRank ensures that your inputs never leave your browser unencrypted. The lightweight Go backend acts solely as an oblivious signaling relay.

✨ Highlights

• Pure Browser Crypto: No heavy WebAssembly or npm bundlers. Implements minimal P-256 elliptic curve operations and utilizes the native Web Crypto API for maximum performance and zero dependencies.
• Dual MPC Protocols: Automatically routes to Yao's Garbled Circuits + Oblivious Transfer for 2 participants, and Additive Secret Sharing for 3+ participants.
• Honest-but-Curious Server Model: The Go backend handles WebSocket relaying but cannot decrypt any payloads. Everything is end-to-end encrypted.
• Single Binary Deployment: The entire vanilla JS frontend is bundled into the Go executable via go:embed for a frictionless ~6MB deployment.

🚀 Getting Started

Prerequisites

• Go 1.21 or higher (for building from source)

Build and Run

# Clone the repository
git clone https://github.com/rihkddd/ZeroRank.git
cd ZeroRank

# Build the single binary
go build -ldflags="-s -w" -o ZeroRank main.go

# Run the server
./ZeroRank -addr :8080

Open your browser and navigate to http://localhost:8080.

Development Mode

If you want to modify the frontend or backend and run the server without building a binary:

go run main.go

🔒 How It Works

ZeroRank uses advanced cryptographic protocols to ensure no one, not even the server, knows your actual input value.

1. 2 Participants (N=2):

   • Uses Yao's Garbled Circuits combined with Chou-Orlandi (2015) Simplest Oblivious Transfer (OT).
   • The garbler creates an encrypted boolean comparison circuit, and the evaluator evaluates it without knowing the original inputs.
   • We implement Point-and-Permute optimization for fast, constant-time gate evaluation.

2. 3+ Participants (N≥3):

   • Uses Additive Secret Sharing over a finite field $Z_p$ (where $p = 2^{61}-1$).
   • Each participant's value is split into random shares and distributed to peers via ECDH + AES-GCM end-to-end encrypted channels.
   • A rotating evaluator reconstructs the difference of shares to securely compare pairwise values.

🛠️ Tech Stack

• Backend: Go (net/http, nhooyr.io/websocket)
• Frontend: Vanilla JavaScript, HTML5, CSS3 (Glassmorphism & Dark Theme)
• Cryptography: Web Crypto API (AES-GCM, ECDH, HKDF, SHA-256), BigInt (P-256 EC math)
• i18n: Built-in support for English and Chinese

📜 License

This project is licensed under the MIT License - see the LICENSE file for details.