Velara – Zcash ↔ Miden Private Bridge

Zypherpunk Hackathon 2025 – Miden Track Submission

Velara is the first private testnet bridge enabling value transfer between Zcash shielded addresses and ** Miden private notes**.
It brings true cross-chain privacy for the first time.

📦 Repository: https://github.com/Web3Novalabs/Velara 👥 Team: Velara Team

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🚨 Problem

As of November 2025, there is no private interoperability between:

• Zcash — the most proven privacy coin
• ** Miden** — a STARK-based zkVM with private local execution

This means:

• No liquidity movement
• No shared privacy ecosystem
• No composable private DeFi
• No way for Zcash users to interact with Miden apps

Velara solves this.

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🎯 Target Users

• Privacy enthusiasts & cypherpunks
• Zcash community members experimenting with Miden
• Hackathon reviewers looking for real, working zk infrastructure
• Future private DeFi users who want privacy across chains

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🌉 What Velara Does (Non-Technical Overview)

Velara lets you move shielded ZEC → private Miden notes (and back).
A full ZEC→Miden bridge flow takes under 5 minutes.

User Flow: Zcash → Miden

1. Visit velara.xyz
2. Click “Bridge from Zcash”
3. Velara instantly generates:
   • A one-time shielded Zcash address
   • A matching Miden receiving address
4. User sends shielded ZEC using Zashi (or any wallet)
5. Velara detects the deposit via lightwalletd
6. User clicks “Claim” in the UI
7. A private pZEC note is created inside their Miden wallet

🔒 No seed phrases exposed
🔒 No amounts made public
🔒 Everything stays private end-to-end

Reverse Flow: Miden → Zcash

• User burns their pZEC note on Miden
• Relayer sends ZEC to a shielded address on Zcash
• Fully private, no public traces

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⚙️ Technical Implementation

✅ Core Features

• One-click Zcash shielded deposit generation
• Miden private note creation
• Real-time Zcash shielded note detection (lightwalletd)
• Claim interface using Miden WebSDK
• Bidirectional transfer (ZEC→Miden live, Miden→ZEC implemented & demo-ready)

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🧩 Architecture Overview

┌─────────────────┐ ┌──────────────────┐ ┌─────────────────┐ │ Frontend │ │ Relayer Node │ │ Miden Testnet │ │ (Next.js) │◄────►│ (Rust + Tokio) │◄────►│ Private Notes │ │ │ │ Watches Zcash │ │ │ └─────────────────┘ └──────────────────┘ └─────────────────┘ ▲ ▲ │ │ ▼ ▼ Zcash Testnet lightwalletd (Shielded TXs) (Block Sync)

Backend / Relayer (Rust)

• Syncs Zcash testnet via lightwalletd
• Extracts Miden public key from shielded memo
• Instantly mints private notes on Miden
• Holds no long-term state (no DB required)

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🧪 Status (Hackathon MVP)

• ✔ ZEC → Miden working
• ✔ Shielded deposits detected live
• ✔ Miden claim UI live
• ✔ Note minting confirmed
• ✔ Miden → ZEC burn implemented
• ✔ Demo-ready end-to-end