HashX — An Optimistic Oracle on Hedera using verifiable timelocked puzzles for delayed consensus.

HashX is an app for creating and resolving prediction markets with accuracy with the help of privacy-preserving voting on Hedera EVM.

Votes are encrypted using BabyJubJub-based ECDH and AES-256-CTR, then revealed via a timelock puzzle or automatically by a server-held key. Rewards are distributed using Merkle proofs.

If you are trying the live deploy link, please try two to three times to deploy the contracts, I observed frequent crashes.

Features

• Verifier Secret Key is generated upon Oracle Creation, Public Parameters for solving the SK is published Onchain (RSA modulus $N$, base $a$, iterations $t$)
• Encrypted voting with EIP‑712 typed signatures → ephemeral keys → AES-encrypted ballot
• Votes are calculated per user basis, Rewards are calculated as per amount staked.
• Voters can not prove what they have voted until the vote is resolved.
• Hedera EVM integration (Testnet) with RainbowKit.
• HBAR staking via HBARLockingContract to obtain voting power. This converts HBAR to WHBAR utilizing WHBAR.sol contract.
• Solver gets certain percentage (default $5%$) of the Oracle value.
• Oracle rewards among voters are distributed via Merkle proofs.
• Postgres DB for fetching markets metadata and serving proofs.

Contracts (addresses on Hedera Testnet)

• HBAR_LOCKING_CONTRACT_ADDRESS: 0xde368C3DCac4E5096f2D2b8AF7Be70277c43b144
• CREATEVOTE_FACTORY_ADDRESS: 0x90Fe5e610A12D2Aa0374e5CEA373bc4CdC103Cbc
• PREDICT_MARKET_FACTORY_ADDRESS: 0x0118250132B55af4Ca1659dA51Bf7430245C1A03
• ABIs: see ABI/
• Only Factory contracts are verified on Hashscan.

Planned Features

• Optional ZK verification with Semaphore, Our app already supports all the necessary features needed for zk encryption.
• Chainlink Oracle integration for real-time price feeds, for markets which don't require Optimistic Oracle
• Scoped Voting, only accepting votes where users have hold to certain onchain NFT.

Tech stack

• App: Next.js (app router), React 19, Tailwind, Zustand, TanStack Query
• Web3: wagmi v2, viem, RainbowKit, SIWE
• Crypto: @zk-kit/baby-jubjub, AES-256-CTR, bigint-mod-arith
• DB: Postgres (Neon)

Prerequisites

• Node 20+ and pnpm 10+
• A Postgres database (Neon recommended)
• A wallet with Hedera Testnet HBAR

Environment

Create .env.local at the repo root:

# Postgres connection string (required)
DATABASE_URL=postgres://user:pass@host/db?sslmode=require

# Server wallet to submit finalize and linkage txs (0x-prefixed; fund with test HBAR)
PRIVATE_KEY=0xYOUR_PRIVATE_KEY

# Optional: custom RPC; defaults to wagmi’s http()
HEDERA_TESTNET_RPC_URL=https://testnet.hashio.io/api

Install, migrate, run

pnpm i

# Run DB migrations (uses drizzle.config.ts)
pnpm dlx drizzle-kit push

# Dev server (TurboPack)
pnpm dev
# Build
pnpm build
pnpm start
# Lint
pnpm lint

How it works

• Create Oracle (Vote):
  • Creator sets rewards and time window; generates public parameters and timelock puzzle.
  • Optionally stores secret key server-side for auto-resolve; otherwise anyone can solve puzzle post‑end.
  • A CreateVote contract is deployed via factory; server verifies on-chain public params against DB.
• Create Prediction Market:
  • After oracle exists, deploy PredictionMarket via factory with initial liquidity and parameters.
  • Server links the oracle to the market (setPredictionMarket) and stores market metadata.
• Vote:
  • User signs typed data (EIP‑712), derives ephemeral BabyJubJub key, and encrypts the chosen option.
  • Submits castVote(userPublicKey, encryptedOption, amount).
• Resolve and claim:
  • After end time, server (or anyone with SK) decrypts logs, tallies votes, builds Merkle trees.
  • Finalizes on-chain with winner root; winners claim via claimRewards(proof).

Using the app

1. Connect wallet. The UI will prompt to add/switch to Hedera Testnet if needed.
2. Stake HBAR (Stake tab) to gain voting power.
3. Create Oracle (Start Creating):
   • Set rewards, start/end time, and choose resolution mode (auto vs manual puzzle).
   • The app records marketId and oracle contractAddress.
4. Create Market: Provide initial liquidity and parameters, then submit.
5. Vote: Pick option, Generate Signature, then Submit Vote.
6. Resolve: After end, click Verify Result (runs decrypt + finalize) and then Claim Rewards.

Scripts

• Solve timelock puzzle interactively:

pnpm dlx tsx src/scripts/solve_puzzle.ts
pnpm dlx tsx src/scripts/timelock_test.ts