Atreus

ZK-gated escrow payment links on Stellar. Create on-chain escrow links with XLM, share a secret URL, and let recipients claim funds by generating a zero-knowledge proof — without ever revealing the secret on-chain.

What It Does

• Wallet Dashboard — View balance, all assets, and recent transactions. Create an instant non-custodial wallet (no browser extension required).
• Send / Receive — Send XLM to any Stellar address. Share your address with an explorer link.
• Swap — XLM → USDC/EURT via Stellar DEX path payments. Trustlines added automatically.
• Payment Links — Create escrow links secured by SHA-256 secrets and ZK proofs. Recipients claim funds by proving secret knowledge without revealing it.
• Manage Assets — Add trustlines for any Stellar asset.

Architecture

Browser (ZK proof)  →  Backend (proof verification)  →  Soroban (on-chain settlement)

Component	Stack	What it does
frontend/	Next.js 15, React 19, Tailwind CSS	Wallet UI + payment link creation/claiming
backend/	Express, TypeScript, bb.js	ZK attestation service — verifies UltraHonk proofs off-chain, signs on-chain attestations
contracts/	Rust, Soroban SDK 22.0.0	Escrow contract + VerifierContract (attestation oracle)
circuits/	Noir 1.0.0-beta.22	Pedersen-based ZK proof circuit

ZK Architecture

Payment links use a real Noir circuit that proves knowledge of a link secret without revealing it. An UltraHonk proof is generated client-side via @aztec/bb.js and verified by a backend attester, which submits an on-chain attestation that the escrow contract checks before releasing funds.

The attester pattern is used because Soroban lacks native BN254 pairing host functions (BLS12-381 is available via CAP-0059, but this toolchain targets BN254). Once CAP-0074 ships native BN254 verification, the attester can be replaced with direct on-chain proof verification:

flowchart LR
    S[Sender] -->|create_link| E[Escrow Contract]
    E -->|escrows tokens| E
    R[Recipient] -->|generates UltraHonk proof| BA[Backend Attester]
    BA -->|verifies proof + submits attest| VC[Verifier Contract]
    VC -->|is_attested=true| E
    E -->|releases funds| R

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Features

Web Wallet

• BIP39 mnemonic (24 words) — recoverable across devices
• Google OAuth sign-in via @react-oauth/google
• Anonymous wallet — create instantly, no account needed
• Wallet restore — recover from seed phrase
• All signing via localStorage keypair — no browser extension required

Payment Links

1. Sender generates a 32-byte secret → SHA-256 hash → create_link() on the escrow contract
2. Recipient opens the URL containing the secret → generates a ZK proof client-side → backend attester verifies the proof and submits an on-chain attestation → claim_link() checks both the secret hash and attestation → funds released

Quick Start

# Frontend
cd frontend
npm install
cp .env.example .env.local   # add your contract IDs and Google Client ID
npm run dev                   # http://localhost:3000

# Backend
cd backend
cp .env.example .env          # set ATTESTER_SECRET_KEY
pnpm dev                      # http://localhost:3001

# Contracts
cd contracts
cargo test -p atreus-contract

# Circuits (via Docker)
docker compose run --rm compile
docker compose run --rm test

Project Structure

atreus/
├── frontend/          Next.js 15 web app
├── backend/           Express API — ZK attestation service
├── contracts/         Soroban smart contracts (Rust)
├── circuits/          Noir ZK circuits
├── docs/              Architecture docs
├── Dockerfile         Node 20 + nargo 1.0.0-beta.22
├── docker-compose.yml
└── pnpm-workspace.yaml

Environment Variables

Frontend (.env.local):

NEXT_PUBLIC_CONTRACT_ID=CCZSFPZ6XPZBUPBGQ5FRP5BMW5HKZIZNCWPLJAHNOWP4ZI7BZSMJDTCD
NEXT_PUBLIC_VERIFIER_CONTRACT_ID=CB3GJLFAGH2WQTQHSMAB7GABK4NC5Q74XDV2U7MWAYEKQV7YMBV2O7KD
NEXT_PUBLIC_TOKEN_ID=CDLZFC3SYJYDZT7K67VZ75HPJVIEUVNIXF47ZG2FB2RMQQVU2HHGCYSC
NEXT_PUBLIC_GOOGLE_CLIENT_ID=your-client-id.apps.googleusercontent.com
NEXT_PUBLIC_BACKEND_URL=http://localhost:3001

Backend (.env):

PORT=3001
ATTESTER_PUBLIC_KEY=<your attester public key>
ATTESTER_SECRET_KEY=<your attester secret key>
NEXT_PUBLIC_CONTRACT_ID=CCZSFPZ6XPZBUPBGQ5FRP5BMW5HKZIZNCWPLJAHNOWP4ZI7BZSMJDTCD
NEXT_PUBLIC_VERIFIER_CONTRACT_ID=CB3GJLFAGH2WQTQHSMAB7GABK4NC5Q74XDV2U7MWAYEKQV7YMBV2O7KD
SOROBAN_RPC_URL=https://soroban-testnet.stellar.org
HORIZON_URL=https://horizon-testnet.stellar.org
FRONTEND_URL=http://localhost:3000

Deployed Contracts (Testnet)

Contract	ID
VerifierContract	CB3GJLFAGH2WQTQHSMAB7GABK4NC5Q74XDV2U7MWAYEKQV7YMBV2O7KD
AtreusContract	CCZSFPZ6XPZBUPBGQ5FRP5BMW5HKZIZNCWPLJAHNOWP4ZI7BZSMJDTCD

Pages

Route	Feature
/	Landing page
/wallet	Create / restore wallet
/dashboard	Balance, assets, transactions
/send	Send XLM
/receive	Receive — copy address
/swap	XLM → token via Stellar DEX
/assets	Add trustlines
/create	Create payment link
/claim	Claim payment link
/activity	Transaction history
/analytics	Wallet analytics
/profile	User profile
/security	Security settings
/settings	Network, address book, notifications

Design

Dark theme with Tailwind CSS and lucide-react icons. Reusable layout components in frontend/src/components/. Navigation items centralized in frontend/src/constants/navigation.ts.

Docs

• Frontend Walkthrough
• Contracts Walkthrough
• Circuits Walkthrough

License

MIT