SolveX — ZK Puzzle Bounty Market

Post a Sudoku puzzle with a USDC bounty.
Prove you solved it on-chain — without ever revealing the solution.

Built on Arc Testnet · Groth16 ZK proofs · Solidity + Foundry · Next.js

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How It Works

1. Post — Creator submits an 81-cell Sudoku puzzle + USDC bounty + deadline
2. Boost — Anyone can top up the prize pool (crowdfunded bounties)
3. Solve — Solver fills the grid in the browser
4. Prove — snarkjs generates a Groth16 ZK proof client-side (~30 s)
5. Claim — Proof submitted on-chain; contract verifies it and releases the bounty
6. Credential — Solver receives a soulbound NFT as proof-of-skill

The ZK circuit enforces all Sudoku rules (row/column/box uniqueness + clue matching). The solver's answer is never revealed on-chain — only the proof is.

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Project Structure

solvex/
├── circuits/           Circom circuit — full Sudoku constraint system
├── contracts/          Foundry project
│   ├── src/
│   │   ├── BountyMarket.sol   Core protocol contract
│   │   ├── SolverNFT.sol      Soulbound credential NFT
│   │   └── interfaces/
│   ├── script/Deploy.s.sol
│   └── test/BountyMarket.t.sol
├── scripts/            Circuit compile + trusted setup + proof generation
└── frontend/           Next.js 14 app (App Router)

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Setup

Prerequisites

• Node.js ≥ 18
• Circom ≥ 2.0 (npm i -g circom)
• Foundry (curl -L https://foundry.paradigm.xyz | bash)
• Arc Testnet USDC from the Circle Faucet

1 — Install dependencies

# Circuit / scripts
cd scripts && npm install

# Contracts
cd ../contracts && forge install \
  OpenZeppelin/openzeppelin-contracts \
  foundry-rs/forge-std

# Frontend
cd ../frontend && npm install

2 — Compile the circuit

cd scripts
bash 1_compile.sh

Outputs artifacts/sudoku.r1cs, artifacts/sudoku_js/sudoku.wasm etc.

3 — Trusted setup

bash 2_setup.sh

Downloads pot14_final.ptau (~85 MB, Hermez ceremony), runs Phase 2 setup, exports contracts/src/Verifier.sol and copies wasm + zkey to frontend/public/.

Production note: For mainnet, run a proper multi-party ceremony rather than a single-contributor setup.

4 — Deploy contracts

cd contracts
cp .env.example .env   # fill in PRIVATE_KEY and VERIFIER_ADDRESS

# Deploy Verifier first
forge create src/Verifier.sol:Groth16Verifier \
  --rpc-url arc_testnet --private-key $PRIVATE_KEY

# Set VERIFIER_ADDRESS in .env, then deploy market + NFT
forge script script/Deploy.s.sol \
  --rpc-url arc_testnet --broadcast --private-key $PRIVATE_KEY

Copy the output addresses into frontend/.env.

5 — Run the frontend

cd frontend
cp .env.example .env   # fill in contract addresses + WalletConnect project ID
npm run dev

Open http://localhost:3000.

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Contracts (Arc Testnet)

Contract	Address
BountyMarket	TBD — fill after deploy
SolverNFT	TBD — fill after deploy
Verifier	TBD — fill after deploy

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Run Tests

cd contracts
forge test -vvv

All 8 unit tests cover: post, contribute, claim, double-claim prevention, expiry, refund, protocol fees, and soulbound transfer revert.

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Generate a Proof (CLI)

cd scripts
node 3_generate_proof.js puzzle.json solution.json
# outputs proof_calldata.json with formatted pA, pB, pC, pubSignals

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Circuit Design

The Sudoku() circuit in circuits/sudoku.circom:

Signal	Visibility	Description
puzzle[81]	public	Clue grid (0 = blank, 1-9 = given)
solution[81]	private	Full solution (never revealed)

Constraints enforced:

• Each solution cell is in [1, 9]
• For every non-zero puzzle cell, solution[i] == puzzle[i]
• Every row contains {1…9} exactly once
• Every column contains {1…9} exactly once
• Every 3×3 box contains {1…9} exactly once

Requires pot14_final.ptau (~16 384 constraints).

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Uniqueness Features

Feature	Description
ZK proofs	Solution privacy guaranteed on-chain
Crowdfunded pools	Anyone adds to the bounty
Soulbound NFT	Non-transferable proof-of-skill credential
2.5% protocol fee	Self-sustaining without a token
Creator refund	Unclaimed pool returned after deadline
On-chain SVG NFT	No IPFS dependency

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Roadmap

• Multi-puzzle-type registry (extend beyond Sudoku)
• Hint micropayments (creator earns from hints)
• Time-escalating bounty curve
• Proof aggregation for gas efficiency
• Mainnet deployment (Arc Mainnet)