EventShield is a decentralized, secure event ticketing marketplace and dynamic anti-scalping protocol built natively on the Arc Network (Chain ID: 5042002). By hardcoding commerce guidelines directly within Solidity EVM primitives, implementing EIP-712 dynamic ticket check-in signatures, and leveraging Circle’s USDC for gasless settle speeds, EventShield prevents bot manipulation, secures ticket payouts, and routes secondary royalties directly to artists.
Important
Arc L1 Network Advantages: EventShield utilizes Arc Network, where native USDC acts as the gas token. This enables fee predictability and native stablecoin settlement. With EventShield's custom Gas Station / /api/sponsor API, end-users experience a completely gasless interface sponsored via Circle Developer APIs.
Traditional event ticketing frameworks are plagued by systemic inefficiencies. Secondary markets are dominated by automated bots that drain primary allocations, inflate ticket resale prices, and leave artists out of secondary trade revenues. At the same time, visual-only QR ticket entry systems are prone to copy-paste screenshot theft and replay exploits.
EventShield shifts the ticketing trust model from off-chain database logic to immutable on-chain enforcement:
- Hardcoded Resale Caps: Resale listings are restricted at the contract level to
originalPrice * (100 + maxMarkupPercentage) / 100. Listing attempts above this limit fail during the EVM transaction phase. - On-Chain Artist Royalties: 10% secondary sales royalties are routed to creator wallets atomically within the same purchase transaction.
- EIP-712 Cryptographic Gate Admission: To block screenshot duplication, checkpoints recover dynamic private signatures generated locally by the holder's wallet.
- Unified Multi-Chain stablecoin liquidity: Fans refuel their ticketing wallets using Circle Unified Balance and CCTP Bridge kits from Base, Ethereum, and Avalanche, and convert EURC to USDC via StableFX.
The EventShield architecture divides protocol responsibilities among four specialized Solidity contracts deployed on the Arc Testnet:
┌────────────────────────────────────────┐
│ EventTicket (ERC-721) │
│ - Primary and secondary sales logic │
│ - Markup caps & 10% secondary royalty │
│ - EIP-712 check-in recovery verification│
└──────────┬──────────┬──────────┬───────┘
│ │ │
checks/registers │ │ │ mints commemorative
attendance count ▼ │ ▼ NFTs upon check-in
┌──────────────────────────────┐ │ ┌──────────────────────────────┐
│ FanRewardRegistry │ │ │ EventCollectible │
│ - Attendance tracking │ │ │ - On-chain base64 NFT drops │
│ - 20-200 USDC cashbacks │ │ │ - Platinum special editions │
│ - Gold+ 24h early access │ │ └──────────────────────────────┘
└──────────────────────────────┘ │
▼
┌──────────────────────────────┐
│ ReferralRegistry │
│ - Affiliate relationships │
│ - 2% USDC platform fee splits│
│ - 5 USDC milestone bonuses │
└──────────────────────────────┘
- USDC Native Gas: Using Arc Network where USDC is the native gas asset avoids complex gas-token bridging UX.
- Double-Spend & Escrow Protection: All primary purchases can escrow funds based on
RefundPolicy(Full, Partial, or No Refund). If an event is cancelled, fans claim refunds which automatically claw back referrer commissions via theReferralRegistry. - Optimized Gate Scans: Scanners parse and verify signatures offline before submitting the on-chain sponsored transaction, minimizing chain load.
The flowchart below demonstrates the transaction and state transitions when minting, listing, reselling, verifying, and claiming reward payouts:
graph TD
classDef default fill:#121214,stroke:#fff,stroke-width:1px,color:#fff;
classDef contract fill:#1a1a1f,stroke:#fff,stroke-dasharray: 5 5,color:#fff;
A[Creator / Organizer] -->|Register Event| B(EventTicket Contract)
C[True Fan] -->|Purchase Ticket with USDC| B
C -->|List Ticket on Resale| D{Price Validation}
D -->|Asked Price <= Cap| E[Approved Resale Listing]
D -->|Asked Price > Cap| F[Transaction Reverted]
G[Secondary Buyer] -->|Purchase Listed Resale| E
E -->|89% Payout| C
E -->|10% Artist Royalty| A
E -->|1% Safety Fee| B
E -->|Transfer NFT| G
G -->|Generate EIP-712 QR Code| H(Gate Agent Scanner)
H -->|Validate Timestamp & Nonce| I{Cryptographic ecrecover?}
I -->|Valid Signature| J[Mark Ticket Used]
I -->|Invalid Signature| K[Access Denied]
J -->|Register Attendance| L(FanRewardRegistry)
L -->|Trigger NFT Commemoration| M(EventCollectible Mint)
L -->|Attended >= 3 Shows| N[Claim USDC Cashback Bounty]
class B,L,M,ReferralRegistry contract;
EventShield features deep, production-grade integrations with the Circle developer and stablecoin suites:
EventShield integrates the @circle-fin/w3s-pw-web-sdk to provision secure, non-custodial Smart Contract Accounts (SCA) for users. Users onboard via social auth, configure a recovery PIN, and sign transactions.
- Frontend Context:
CircleWalletContext.tsxhandles device ID initialization, PIN creation challenges, and session renewals. - EIP-712 Signing: Used to sign EIP-712 ticket validation hashes locally, bypassing standard gas requirements.
- Organizers reserve payouts: Autonomous payouts are executed from the developer-controlled organizer wallet (
CIRCLE_ORGANIZER_WALLET_ID) using the@circle-fin/developer-controlled-walletsSDK. - Bounty Claims: Eligible fans claiming cashbacks from
FanRewardRegistryreceive automatic on-chain USDC payouts sponsored by the organizer.
To provide a completely gasless experience, all write operations (purchases, listings, check-ins, claims) route through a Next.js API proxy (/api/sponsor) that interacts with Circle Programmable Wallets to sponsor gas.
Warning
Sponsorship Security Controls:
- Whitelist Filtering: Sponsoring is restricted strictly to the 4 whitelisted EventShield contract addresses and 9 specific function signatures.
- USDC Approve Restrictions: If the call is
approve(address,uint256)on the USDC contract, the spender address must be theEventTicketcontract. Users cannot exploit the Gas Station to approve external drainers. - Rate Limiting: Wallets are rate-limited to 10 sponsored transactions per hour.
// Core implementation from frontend/src/app/api/sponsor/route.ts
const response = await circleClient.createUserTransactionContractExecutionChallenge({
userToken,
walletId,
contractAddress,
abiFunctionSignature,
abiParameters: abiParameters || [],
fee: { type: 'level', config: { feeLevel: 'MEDIUM' } },
});Fans can spend USDC residing on other chains without manually bridging first. The frontend incorporates useUnifiedBalance to query balances across Base Sepolia, Ethereum Sepolia, Avalanche Fuji, and Arc Testnet, and executes direct ticket purchases:
const result = await appKit.unifiedBalance.spend({
from: { adapter },
to: { recipientAddress: destAccount, chain: 'Arc_Testnet', useForwarder: true },
amount,
token: 'USDC'
});For manual balance management, CircleBridgeKit.tsx provides an interface to execute CCTP native burn-and-mint transfers. It includes a cryptographic debugger displaying the burn hash, source/destination domain IDs, and Circle Attestation API requests (https://iris-api-sandbox.circle.com/v1/attestations/...).
EventShield supports converting EURC (Euro stablecoin) to USDC using Circle's StableFX API and the Permit2 verifying contract (0x000000000022D473030F116dDEE9F6B43aC78BA3). Users sign a PermitWitnessTransferFrom message to execute EURC conversions atomically:
const quoteSignature = await signTypedDataAsync({
domain: quote.typedData.domain,
types: quote.typedData.types,
primaryType: quote.typedData.primaryType,
message: quote.typedData.message
});EventShield implements an on-chain AI agentic swarm using the ERC-8004 standard for Agent Identity, Reputation, and Validation Registries. The swarm consists of 4 agents managed by the CopilotPanel chatbot interface:
┌────────────────────────────────────┐
│ MasterAgent (Orchestration Router) │
└─────────────────┬──────────────────┘
│
┌──────────────────────────┼──────────────────────────┐
▼ ▼ ▼
┌────────────────────────┐ ┌────────────────────────┐ ┌────────────────────────┐
│ OpsAgent │ │ LoyalAgent │ │ GuardAgent │
│ - Configures payloads │ │ - Payouts USDC cashbacks│ │ - Verifies gate ticket │
│ - Reads contract states│ │ - Circle dev-wallets │ │ signatures (EIP-712) │
└────────────────────────┘ └────────────────────────┘ └────────────────────────┘
- MasterAgent (Orchestration Router): Routes user prompts to the correct sub-agent.
- OpsAgent (Dynamic Event Configurator):
- Configures deployment parameters for new events (prices, markup caps, dates).
- Automatically reads the next event ID from the on-chain ticket registry.
- LoyalAgent (Loyalty & Payout Automation):
- Queries
FanRewardRegistryon-chain to verify check-in requirements. - Triggers the Developer-Controlled Wallet API to payout USDC cashbacks to eligible fans.
- Queries
- GuardAgent (Anti-Scalp & Signature Protection):
- Queries
EventTicketticket mappings on-chain. - Inspects ticket state, seat, and check-in statuses.
- Queries
The EventShield Gatekeeper Agent is registered on the Arc Testnet with Agent ID 800401 under the following ERC-8004 contract addresses:
- Identity Registry:
0x8004A818BFB912233c491871b3d84c89A494BD9e(NFT registration with IPFS metadata URI) - Reputation Registry:
0x8004B663056A597Dffe9eCcC1965A193B7388713(Validator feedback score: 98/100) - Validation Registry:
0x8004Cb1BF31DAf7788923b405b754f57acEB4272(KYC verification status:kyc_verified)
To prevent screenshot replication, ticket entry codes expire after 15 seconds. The ticket holder's client wallet generates a signature based on EIP-712 structured data:
bytes32 public constant CHECKIN_TYPEHASH = keccak256(
"CheckInRequest(uint256 tokenId,address owner,uint256 timestamp,uint256 nonce)"
);- Nonce Check: The client queries the current check-in nonce
checkInNonces[owner]fromEventTicket. - Timestamping: The client signs the hash using a current UNIX timestamp.
- QR Construction: The client encodes the signature, tokenId, owner address, timestamp, and nonce into a dynamic QR code.
- Scanner Validation:
- The scanner parses the QR code.
- It checks:
block.timestamp - timestamp <= 90seconds (prevents old screenshot playback). - It checks:
timestamp <= block.timestamp + 30seconds (allows minor clock drift). - It executes
ecrecoveron-chain or off-chain to verify the signer matches the ticket owner. - The transaction is sent to
checkInTicket, incrementing the owner's nonce to prevent replay attacks.
Both contracts are compiled using Solidity 0.8.20 with EVM Shanghai settings and are verified on Arc Testnet:
| Contract Name | Arc Testnet Address | Blockchain Explorer link |
|---|---|---|
| EventTicket (ERC-721) | 0x47e9dfBB189601B0FE25c26d75a11C266b22E82D |
View on ArcScan |
| FanRewardRegistry | 0x49a7192C113c46923c542D406a956c31c6D5c677 |
View on ArcScan |
| ReferralRegistry | 0xB04cb31DAF7788923b405B754F57acEB4272113C |
View on ArcScan |
| EventCollectible (NFT) | 0xbc8F266A48F95F319D72a8004B663056A597Dffe |
View on ArcScan |
| Native USDC Gas Token | 0x3600000000000000000000000000000000000000 |
View on ArcScan |
| Function Signature | Scope | Core Protocol Rules |
|---|---|---|
createEvent(CreateEventParams params) |
Event Launch | Configures price, seat limit, refund policy, and markup cap (Max royalty capped at 50%) |
purchasePrimaryTicket(eventId, seatNo) |
Primary Sale | Mints ticket, applies loyalty discounts (Silver 5%, Gold 10%, Platinum 15%), and tracks referral commission (2%) |
listTicketForResell(tokenId, askedPrice) |
Resale | Validates requested price against markup cap; reverts if price is exceeded |
buyResellTicket(tokenId) |
Resale | Atomically transfers NFT, distributes 10% royalty to artist, 1% fee, and seller portion |
checkInTicket(tokenId, owner, timestamp, signature) |
Gate Entry | Cryptographically verifies owner signature, enforces 90s time window, registers attendance, and mints NFT |
claimLoyaltyReward() |
Cashback | Distributes 20 USDC to fans with 3+ check-ins (Bronze tier) |
claimTierReward(tier) |
Multi-tier claims | Claims cashbacks for higher tiers (Silver: 50 USDC, Gold: 100 USDC, Platinum: 200 USDC) |
claimCommissions() |
Referrals | Claims accrued affiliate referral commissions from ReferralRegistry |
Handles backend user and wallet creation inside the Circle developer dashboard.
- Actions:
init-session(Generates user tokens/encryption keys),init-wallet(Launches PIN challenge),execute-contract(Standard contract write payload),sign-typed-data(Generates signatures),get-latest-tx(Queries transaction hashes).
{
"action": "init-session",
"email": "[email protected]"
}{
"success": true,
"userId": "fan_fan_eventshield_io",
"userToken": "eyJhbGciOi...",
"encryptionKey": "MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA...",
"hasWallet": true,
"walletAddress": "0x6fB123893a74F2Cc117E3d0e98EC3A92A69A1234",
"walletId": "b8a82d0b-6a51-55c1-83d6-b927e4054050"
}Coordinates Gas Station sponsorships for whitelisted actions.
- Actions:
GET(Retrieves sponsor analytics),POST(Sponsors a smart contract write or deposits funding).
{
"userToken": "eyJhbGciOi...",
"walletId": "b8a82d0b-6a51-55c1-83d6-b927e4054050",
"contractAddress": "0x47e9dfBB189601B0FE25c26d75a11C266b22E82D",
"abiFunctionSignature": "purchasePrimaryTicket(uint256,string)",
"abiParameters": ["1", "Seat A12"]
}{
"success": true,
"challengeId": "a90b8c6d-927e-4050-b55c-1c229255a6d2",
"isGasSponsored": true,
"analytics": {
"totalSponsoredTxCount": 104,
"totalGasSponsoredUSDC": 0.52,
"treasuryBalance": 249.48,
"functionCalls": {
"purchasePrimaryTicket(uint256,string)": 42
}
}
}Coordinates NLP commands to the specialized agentic swarm.
{
"command": "verify signature of ticket #12",
"address": "0x6fB123893a74F2Cc117E3d0e98EC3A92A69A1234"
}{
"success": true,
"agent": "GuardAgent (Anti-Scalp & Signature Protection)",
"response": "GuardAgent has verified Ticket #12 on the Arc L1 blockchain. The ticket is currently active and unused, assigned to Seat \"Seat A12\", with a secondary markup resell cap of +20% strictly enforced.",
"steps": [
"[GuardAgent] Connecting to ticket registry contract...",
"[GuardAgent] Querying contract mapping at address: 0x47e9dfBB189601B0FE25c26d75a11C266b22E82D",
"[GuardAgent] Target Token ID resolved: 12",
"[GuardAgent] Ticket details fetched -> Event ID: 1 | Original Price: 20 USDC | Cap: 20% | Seat: Seat A12",
"[GuardAgent] Gate Entry Status: ACTIVE (UNUSED)"
],
"actionResult": {
"status": "VERIFIED",
"ticketId": "12",
"eventId": "1",
"originalPrice": "20 USDC",
"maxMarkupPercent": "20",
"artistWallet": "0xbc8F266A48F95F319D72a8004B663056A597Dffe",
"isUsed": false,
"seatNumber": "Seat A12"
},
"agentId": "800401",
"timestamp": "2026-07-01T07:42:07.123Z"
}- Node.js (v18.x or greater)
- Hardhat framework tools
Navigate to the contracts directory, install dev packages, and execute the deployer script:
cd contracts
npm install
npm run compile
npm run deployThe deploy script compiles all solidity contracts, launches them onto the Arc network, links registry addresses, and updates frontend ABIs and addresses in frontend/src/lib/constants.ts automatically.
To register the AI Gatekeeper Agent under the ERC-8004 standard on-chain, run:
node scripts/register-agent.mjsConfigure environment variables in frontend/.env.local:
NEXT_PUBLIC_CIRCLE_APP_ID=b75a0a0f-07b0-5422-abc8-f309252d8cb0
NEXT_PUBLIC_CIRCLE_CLIENT_KEY=TEST_CLIENT_KEY:...
NEXT_PUBLIC_CIRCLE_CLIENT_URL=https://modular-sdk.circle.com/v1/rpc/w3s/buidl
CIRCLE_API_KEY=TEST_API_KEY:...
CIRCLE_ENTITY_SECRET=27272eee7b9b055e00affc54a2c994f695e58117cb93afeb6864f8da4b021ec4
CIRCLE_ORGANIZER_WALLET_ID=e1cb7936-4a51-55c1-83d6-b927e4054050Start the Next.js development server:
cd ../frontend
npm install
npm run devNavigate to http://localhost:3000 to interact with the platform.