A privacy-first, cross-chain wallet solution addressing all 7 tracks of the Zypherpunk Hackathon
.png){kind=link}
Zephyr is a comprehensive privacy-first wallet solution built on the OASIS platform. It provides a unified interface for managing assets across multiple privacy-focused blockchains, with built-in support for private bridges, stablecoin minting, and advanced privacy features.
Built for: Zypherpunk Hackathon (Nov 12 - Dec 1, 2025)
We've built infrastructure that solves critical problems in the privacy-first, cross-chain DeFi ecosystem. Our solution doesn't just address hackathon requirements—it creates the foundation for the future of private finance.
The Problem:
- Every blockchain ecosystem lives in isolation
- Users need multiple wallets, remember different seed phrases, learn different UIs
- Privacy chains can't easily communicate with each other or with public chains
- Liquidity is fragmented across isolated ecosystems
Our Solution:
- Single wallet for 6 chains (Zcash, Aztec, Miden, Starknet, Solana, Ethereum)
- One keypair works across all chains via unified address derivation
- Cross-chain bridges with privacy preserved
- OASIS provider abstraction connects ecosystems without breaking them
Impact:
- Increased adoption for each chain through unified interface
- More liquidity as assets flow between chains
- Interoperability while preserving each chain's unique features
- Easier onboarding for new users
The Problem:
- Privacy chains have amazing technology but terrible UX
- Learning curve is steep: shielded addresses, viewing keys, notes, etc.
- Most users avoid privacy features because they're too complicated
- No easy way to use private assets in DeFi protocols
Our Solution:
- Wallet UI that makes privacy chains as easy to use as MetaMask
- zUSD stablecoin: First truly private stablecoin backed by ZEC
- Privacy dashboard that explains privacy levels in plain language
- Viewing keys enable compliance without breaking privacy
- Auto-calculations remove complexity (e.g., zUSD minting)
- Mobile-first design that works like modern apps
Impact:
- Privacy becomes default, not optional
- Regular users can access advanced privacy features
- Financial privacy is accessible to everyone, not just crypto natives
- Sets new standard for privacy-first wallet UX
What Makes This Special:
- Provider abstraction layer that unifies chains with completely different architectures
- Holonic architecture enables privacy-preserving data structures
- Universal Asset Bridge works across all chains
- Single keypair derivation for all supported chains
Why This Technical Approach Matters:
- Each chain keeps its unique features (Zcash's shielded pools, Aztec's private notes, Miden's STARK proofs)
- OASIS enables interoperability without breaking what makes each chain special
- Provider pattern makes it easy to add new chains
- Privacy features (viewing keys, shielded transactions) work across ecosystems
- Foundation for future cross-chain privacy innovations
| Track | Sponsor |
|---|---|
| Track 1 | Aztec Labs - Private Bridge |
| Track 2 | Aztec Labs - Zcash <> Aztec Wallet |
| Track 3 | Aztec Labs - Zcash Backed Stablecoin |
| Track 4 | Miden - Private Bridge |
| Track 5 | pump.fun - Solana ↔ Zcash |
| Track 6 | Helius - Solana ↔ Zcash |
| Track 7 | Self-Custody & Wallet Innovation |
- Single Keypair for Zcash, Aztec, Miden, Starknet, Solana, Ethereum
- Unified Balance View across all chains
- Cross-Chain Transactions with privacy preservation
- Real-time Price Data from CoinGecko
- Transaction History with privacy indicators
- Bi-directional Bridge between Zcash ↔ Aztec
- Privacy Options: Partial notes, viewing keys
- Bridge History tracking and status monitoring
- Atomic Swaps with automatic rollback
- Mint zUSD with ZEC collateral (150% minimum ratio)
- Redeem zUSD to unlock ZEC
- Position Health Monitoring (safe/warning/danger/liquidated)
- Liquidation System for undercollateralized positions
- Yield Generation (5% APY)
- Risk Management with automated health checks
- Privacy Dashboard with metrics and scoring
- Viewing Key Management for auditability
- Shielded Transaction Support
- Privacy Recommendations based on activity
- Privacy Score Calculation
Avatar Authentication: The wallet uses OASIS avatar authentication to securely connect your identity. When you sign in with your avatar credentials, the system automatically links to the Keys/Wallet API and generates wallet addresses for all supported providers (Zcash, Aztec, Miden, Starknet, Solana, Ethereum) from a single keypair. This unified approach eliminates the need for multiple seed phrases while maintaining full self-custody.
Wallet Home Screen: The main dashboard displays your total balance across all chains, along with quick access to all wallet functions including sending, receiving, swapping, privacy features, and stablecoin operations.
| Send Screen | Shielded Transaction |
|---|---|
 |
 |
| Send Screen: Send tokens across any supported chain with privacy options. The interface supports both transparent and shielded transactions, with automatic address validation and transaction fee estimation. | Shielded Transactions: Execute private transactions on Zcash and Aztec networks. Shielded transactions hide sender, recipient, and amount while maintaining full functionality. The wallet automatically manages shielded pools and viewing keys. |
| Privacy Drop | Claim Privacy Drop |
|---|---|
 |
 |
| Privacy Drop: Create and distribute private airdrops to multiple recipients. Privacy drops use shielded addresses to ensure recipient privacy while allowing the sender to track distribution through viewing keys. | Claim Privacy Drop: Recipients can claim privacy drops using their shielded addresses. The system automatically detects available drops and provides a simple one-click claiming interface while maintaining complete privacy. |
Asset Overview: View all available assets across your multi-chain wallets. The interface shows balances for each chain (including SOL and Zcash as shown), with real-time price data and quick access to detailed views for each asset.
.png)
Token Details: Detailed view of individual tokens showing current balance, price history from CoinGecko, transaction history, and asset-specific actions. The price charts provide historical context for informed decision-making.
| Swap Asset Screen | Choose Asset for Swap |
|---|---|
 |
 |
| Swap Interface: Initiate cross-chain swaps between any supported assets. The interface shows exchange rates, estimated fees, and transaction time. Swaps use atomic swap technology to ensure security. | Asset Selection: Choose from a wide range of supported assets for swapping. The wallet supports swaps between Zcash, Aztec, Solana, Ethereum, Starknet, and Miden, with real-time balance checking and availability indicators. |
- ZEC sitting idle—now can be used as stablecoin collateral
- Limited DeFi options—bridge to Aztec opens private DeFi
- Complex shielded transaction UX—simplified in unified wallet
- Value Delivered: New use cases for ZEC holders, access to private DeFi, easier onboarding
- Need for reliable collateral for stablecoins—ZEC is proven, private, valuable
- User acquisition—bridge from Zcash brings established privacy coin users
- Wallet fragmentation—unified wallet removes friction
- Value Delivered: Better stablecoin design with ZEC backing, access to Zcash user base, improved UX
- Isolation from other privacy chains—integrated into broader ecosystem
- Proof of interoperability—demonstrates STARK-based privacy can work with other systems
- User onboarding—unified wallet makes Miden more accessible
- Value Delivered: Integration into privacy-first cross-chain ecosystem, proof of concept for STARK-based privacy interoperability
- Limited privacy options—access to privacy chains via bridges
- User wants privacy—can access Zcash/Aztec without leaving Solana tools
- Fragmentation—unified wallet experience
- Value Delivered: Privacy features through cross-chain bridges, access to private chains without ecosystem lock-in
What We Actually Built:
- 15,000+ lines of production code
- 30+ React components for frontend
- 20+ API endpoints for backend
- 6 blockchain providers integrated
- Complete error handling, loading states, user feedback
- Documentation and guides
Real Features:
- Working wallet creation and management
- Functional stablecoin mint/redeem
- Bridge interface with order tracking
- Privacy dashboard with metrics
- Price charts and transaction history
- QR code generation
This is not just a hackathon proof-of-concept—it's real infrastructure ready for real users.
-
Clone the repository
git clone https://github.com/NextGenSoftwareUK/zypherpunk.git cd zypherpunk -
Run setup script
chmod +x scripts/setup.sh ./scripts/setup.sh
-
Start OASIS API
The wallet requires the OASIS API backend. You have two options:
Option A: Use Existing OASIS API
# If you have access to OASIS API repository git clone <oasis-api-repo> cd oasis-api/ONODE/NextGenSoftware.OASIS.API.ONODE.WebAPI dotnet run
Option B: Use Public API
# Update frontend/.env.local NEXT_PUBLIC_OASIS_API_URL=https://api.oasisplatform.world -
Start Frontend
cd frontend npm run dev -
Open Browser
http://localhost:3000
zypherpunk/
├── frontend/ # Next.js wallet UI
│ ├── app/ # Next.js app router
│ │ ├── wallet/ # Wallet pages
│ │ └── api/ # API proxy routes
│ ├── components/ # React components
│ │ ├── wallet/ # Wallet components
│ │ ├── bridge/ # Bridge components
│ │ ├── stablecoin/ # Stablecoin dashboard
│ │ └── privacy/ # Privacy features
│ ├── lib/ # Utilities and API clients
│ │ ├── api/ # API clients
│ │ └── privacy/ # Privacy utilities
│ └── public/ # Static assets
├── backend/ # API controllers and managers
│ ├── Controllers/ # API endpoints
│ │ ├── StablecoinController.cs
│ │ └── BridgeController.cs
│ ├── Services/ # Business logic
│ │ └── BridgeService.cs
│ └── Managers/ # Core managers
│ └── Stablecoin/ # Stablecoin system
├── docs/ # Documentation
│ ├── ZYPherPUNK_SUBMISSION_RECAP.md
│ └── ZYPherPUNK_TRACK_SPECIFIC_BRIEFS.md
└── scripts/ # Setup scripts
└── setup.sh
- Navigate to wallet page
- Click "Create Wallet"
- Wallets are automatically created for all supported chains
- Ensure you have testnet tokens (ZEC and SOL)
- Navigate to Bridge screen
- Select direction (Zcash → Solana)
- Enter amount and destination address
- Click "Bridge" and monitor status
- Navigate to Stablecoin dashboard
- Ensure you have ZEC for collateral
- Go to "Mint" tab
- Enter ZEC amount and zUSD amount
- Click "Mint" and monitor position
- Submission Recap - Comprehensive overview
- Track Implementation - Detailed track breakdown
- Stablecoin Implementation - Stablecoin system details
- Framework: Next.js 14 with App Router
- Language: TypeScript
- Styling: Tailwind CSS
- UI Components: shadcn/ui
- State Management: Zustand
- Charts: Recharts
- QR Codes: qrcode.react
- Framework: .NET Core 8
- Architecture: OASIS Provider System
- Storage: MongoDB / LocalFile
- Providers: ZcashOASIS, AztecOASIS, MidenOASIS, StarknetOASIS, SolanaOASIS, EthereumOASIS
- Address Derivation: Blockchain-specific (Keccak-256, Ed25519, Pedersen Hash, Bech32)
- Price Oracle: CoinGecko API
- Bridge: Atomic swaps with technical accounts
- Privacy: Viewing keys, shielded transactions, partial notes
The wallet generates addresses for all supported chains from a single keypair using blockchain-specific derivation methods. This eliminates the need for multiple seed phrases while maintaining compatibility with each chain's native address format.
How It Works:
- Single Keypair Generation: A master keypair is generated using standard cryptographic methods
- Provider-Specific Derivation: Each blockchain's address is derived from the public key using that chain's specific algorithm
- SDK Integration: Native SDKs ensure addresses are valid and compatible with each blockchain's ecosystem
Integrated SDKs:
| Provider | SDK/Library | Purpose | Address Format |
|---|---|---|---|
| Starknet | StarkSharp | Pedersen hash for address derivation | 0x + 64 hex chars (66 total) |
| Zcash | Nerdbank.Zcash | Unified Address generation (transparent + shielded) | utest1... / u1... (Bech32m) |
| Ethereum | Nethereum | Keccak-256 hashing for address derivation | 0x + 40 hex chars (42 total) |
| Solana | Solnet | Ed25519 public key encoding | Base58 (32-44 chars) |
| Miden | Miden Python SDK | Bech32 address encoding | mtst1... / mid1... (37 chars) |
| Bitcoin/Zcash | NBitcoin | RIPEMD160, Base58 encoding | Legacy formats |
| Cryptography | BouncyCastle.Crypto | General cryptographic operations | Various |
Address Derivation Methods:
- Ethereum/EVM Chains: Keccak-256 hash of public key → last 20 bytes →
0xprefix - Starknet: Pedersen hash of (account_class_hash, pedersen_hash(public_key, salt), constructor_calldata_hash) → 32 bytes →
0xprefix - Zcash: SHA256 → RIPEMD160 → TransparentP2PKHReceiver → UnifiedAddress (Bech32m)
- Solana: Ed25519 public key (32 bytes) → Base58 encoding
- Miden: Public key → Miden SDK address generation → Bech32 encoding (
mtst1...for testnet) - Aztec: Uses Ethereum-style addresses (Keccak-256 derivation)
Implementation Location:
- Core derivation logic:
OASIS Architecture/NextGenSoftware.OASIS.API.Core/Helpers/AddressDerivationHelper.cs - Frontend integration:
zypherpunk-wallet-ui/lib/unifiedWallet.ts - Backend API: Wallet creation endpoints automatically generate addresses for all providers
Benefits:
- Single Seed Phrase: One mnemonic generates all addresses
- Native Compatibility: Each address format matches the blockchain's standard
- SDK Validation: Native SDKs ensure addresses are valid and accepted by wallets/exchanges
- Future-Proof: Easy to add new chains by implementing their derivation method
Create frontend/.env.local:
# OASIS API URL
NEXT_PUBLIC_OASIS_API_URL=https://localhost:5004
# Use API proxy (for self-signed certificates)
NEXT_PUBLIC_USE_API_PROXY=trueThe wallet connects to OASIS API endpoints:
- Authentication:
/api/avatar/authenticate - Wallet:
/api/wallet/* - Bridge:
/api/v1/orders - Stablecoin:
/api/v1/stablecoin/*
Our Approach:
- Privacy built into the foundation, not bolted on
- Viewing keys enable compliance without breaking privacy
- Privacy metrics help users understand their exposure
- Cross-chain privacy that works seamlessly
Compliance Without Compromise:
- Viewing keys allow selective disclosure for auditors/regulators
- Privacy preserved by default, transparency when needed
- Proof that privacy and compliance can coexist
User Education:
- Privacy dashboard explains privacy levels
- Recommendations help users improve their privacy
- Makes complex concepts (viewing keys, shielded transactions) accessible
| Stakeholder | Problem Solved | Value Delivered |
|---|---|---|
| Users | Complex privacy UX, fragmented wallets | Simple, unified, privacy-first experience |
| Zcash | Limited use cases, isolated ecosystem | Access to private DeFi, stablecoin collateral |
| Aztec | User acquisition, collateral sourcing | ZEC-backed stablecoin, bridge from Zcash |
| Miden | Ecosystem isolation | Integration into privacy-first ecosystem |
| Solana | Limited privacy options | Privacy via cross-chain bridges |
| Industry | Fragmented privacy solutions | Unified infrastructure for privacy-first DeFi |
This is a hackathon submission. For questions or feedback:
- Issues: Open an issue on GitHub
- Repository: https://github.com/NextGenSoftwareUK/zypherpunk
MIT License
- OASIS Platform - Infrastructure and provider system
- Zcash Foundation - Privacy technology
- Aztec Labs - Private smart contracts
- Miden - Zero-knowledge VM
- All Hackathon Sponsors - For the opportunity
- Frontend Components: 30+ React components
- Backend Controllers: 3 major controllers
- API Endpoints: 20+ REST endpoints
- Blockchain Providers: 6 providers
- Lines of Code: ~15,000+
- Tracks Addressed: 7/7 (100%)
- Repository: https://github.com/NextGenSoftwareUK/zypherpunk
- OASIS Platform: https://oasisweb4.one
- Hackathon: https://zypherpunk.xyz/
Built for the Zypherpunk Hackathon 2025
Zephyr: Privacy-first. Cross-chain. Unified.