Place Your Prediction
Quietly.

ShieldOdds is a privacy-preserving prediction market where your bet amount stays encrypted on-chain via FHE, while bet directions and market outcomes remain fully public and verifiable.

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Type
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Bets
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Ends
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Your bet amount is encrypted — directions stay public
Hidden Bet Sizes
Sepolia Live
FHE Verified
How It Works

Four Steps to
Confidential Predictions

ShieldOdds uses Fully Homomorphic Encryption (FHE) so no one can see how much you bet until settlement. Your bet direction (YES/NO) is public; only the bet size is shielded — preventing whale tracking and size-based front-running.

1
Deposit ETH
Send ETH to the contract to fund your encrypted internal balance. Deposit amounts are visible, but your balance becomes encrypted on-chain.
Encrypted Balance
2
Place Hidden-Size Bets
Pick YES or NO publicly, but your bet amount is encrypted client-side via FHE before hitting the chain. No one can see your bet size.
Amount Encrypted
3
Resolve & Settle
After the deadline, the Chainlink oracle reads the live price and auto-resolves the outcome. The KMS decrypts all bet amounts with proof, and the contract computes pro-rata payouts.
KMS Verified
4
Claim Winnings
Winners withdraw their share of the pool proportional to their bet. If no one bet on the winning side, everyone gets a full refund.
1% Protocol Fee
Compare

ShieldOdds vs Polymarket

Traditional prediction markets expose every bet to the public. ShieldOdds changes the game with FHE-encrypted bet amounts — preventing whale tracking and size-based front-running.

FeatureShieldOddsPolymarket
Bet AmountEncrypted — hidden until settlementPublic — visible to everyone on-chain
Bet DirectionPublic and transparent (YES/NO)Public and transparent
Whale Tracking✓ Prevented — bet sizes are encrypted, no one can identify whale positions✗ Exposed — large bets are visible and easily tracked
Size-based Front-running✓ Eliminated — bet amounts are hidden so bots can't front-run large bets✗ Vulnerable — bots detect and front-run large orders in real time
Privacy TechnologyFully Homomorphic Encryption (FHE) via Zama fhEVMNone — standard EVM with public state
SettlementOn-chain via KMS-verified FHE decryptionOff-chain oracle (UMA Optimistic Oracle)
NetworkSepolia (testnet) with FHE coprocessorPolygon (mainnet)
Under the Hood

What's Public, What's Private

Your bet direction (YES/NO) is public for transparency — but your bet amount stays encrypted until settlement, preventing whale tracking.

1
Depositing & Betting
ETH deposit amount
Your wallet address
YES or NO direction
Bet amount (encrypted via FHE)
2
During Market
Number of bets placed
Bet directions (YES/NO per bet)
Individual bet amounts (FHE ciphertext)
Total pool size (encrypted sum)
3
Settlement
Market outcome (YES/NO)
Decrypted bet amounts (KMS-verified)
Payout amounts per winner
Protocol fee (1%)
Public on-chain
FHE Encrypted
Tech Stack

Built on Proven Infrastructure

Every component is chosen for security, verifiability, and performance.

Encryption
Zama fhEVM
Fully Homomorphic Encryption protocol that enables encrypted computation directly on-chain. Bet amounts stay hidden even from the contract itself.
Smart Contracts
Solidity + FHEVM
Solidity contracts using Zama's FHE library for encrypted types (euint64), on-chain encryption, KMS decryption proofs, and access control.
Network
Sepolia Testnet
Deployed on Ethereum's Sepolia testnet with Zama's FHE coprocessor. Free testnet ETH — no real funds at risk during development.
Development
Hardhat
Industry-standard Ethereum development framework. Automated testing, deployment scripts, and task-based CLI for market management.
Live Markets

Active Prediction Markets

Deposit ETH to fund your encrypted balance, then place bets on any open market. Bet amounts are encrypted — only the direction is visible.

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Connecting to Sepolia to fetch live data.

FAQ

Frequently Asked Questions

Everything you need to know about ShieldOdds.

What is FHE and why does it matter?
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Fully Homomorphic Encryption (FHE) allows computation on encrypted data without ever decrypting it. In ShieldOdds, this means the smart contract processes your bet without knowing how much you wagered. Your bet amount stays encrypted on-chain until the market is settled and KMS-verified decryption reveals all amounts simultaneously for payout calculation.
What exactly is encrypted vs public?
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Only your bet amount is encrypted. Your bet direction (YES or NO), wallet address, and the market details are all public on-chain. This prevents whale tracking and size-based front-running while keeping bet directions transparent. At settlement, bet amounts are decrypted for payout calculation.
How does this prevent front-running?
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In traditional prediction markets, everyone can see how much you're betting. Bots and whales exploit this by front-running large bets — placing their own bets first to manipulate the odds. Since ShieldOdds encrypts your bet amount, no one can identify large positions to front-run. Bet sizes are only revealed during settlement, after all bets are locked in.
How are payouts calculated?
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Payouts are pro-rata: your share of the total pool is proportional to your bet relative to all winning bets. A 1% protocol fee is deducted from the pool before distribution. If no one bet on the winning side, all bettors receive a full refund (no fee applied).
What network is ShieldOdds on?
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ShieldOdds is deployed on Ethereum's Sepolia testnet with Zama's FHE coprocessor. This is a testnet deployment — you use free Sepolia ETH, not real funds. You can get testnet ETH from any Sepolia faucet.
Who resolves the market outcome?
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For crypto price markets, resolution is automatic via Chainlink oracle. After the deadline, anyone can trigger resolution — the contract reads the live price directly from Chainlink's on-chain price feed and determines the outcome (e.g., did BTC reach $100k?). No human input needed. For custom markets without a price feed, the creator resolves manually. After resolution, the settlement process decrypts all bet amounts using KMS-verified proofs and computes pro-rata payouts.
What wallet do I need?
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Any Ethereum-compatible wallet that supports Sepolia testnet works — MetaMask, Rabby, or similar. The app will automatically prompt you to switch to Sepolia (chain ID 11155111) when you connect.
What is the minimum bet?
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The minimum bet is 0.001 ETH (enforced in the frontend). First deposit ETH to create your encrypted on-chain balance, then place bets from that balance. Since this is a testnet, the ETH has no real monetary value — you can get it free from Sepolia faucets.