TLaaS (LEX) — License Marketplace DApp: Escrow & Trading Interface Architecture

1. Purpose

Design and implement a non-custodial, upgradeable marketplace for tokenized licenses (ERC-721/1155) with escrowed settlement, sublicensing flows, and governance-aware dispute hooks. The marketplace must interoperate with TLAAS (DLA) for validation gates and with DAL for override routing and arbitration. UX must support: list, buy-now, offers, auctions (optional), sublicensing, renewals, and revocations—backed by cryptographic receipts and fully auditable logs.

2. System Architecture (High-Level)

• Smart Contracts (EVM):
• LicenseMarketplace
• EscrowVault
• SublicenseModule
• OverrideRouter
• Compliance Layer:
• Payment Layer:
• Oracle Layer: For fiat confirmations & FX normalization.
• Indexing: Off-chain indexer (The Graph / custom) for orders, fills, cancellations, disputes.
• Front-End (DApp): Wallet connect, order book UI, escrow status tracker, dispute center, validator view.

3. Data Model & Schemas

3.1 Order (EIP-712 signed)

• maker
• asset
• id
• amount
• paymentToken
• price
• expiry
• salt
• constraints
• jurisdiction
• side

3.2 Trade Receipt

• orderHash
• taker
• paid
• timestamp
• escrowId

4. Protocol Flows

4.1 List (ASK)

1. Maker signs EIP-712 order off-chain.
2. DApp posts order to indexer; no gas spent until match.
3. On match, contract verifies signature, checks TLAAS compliance, opens escrow.

4.2 Buy Now

1. Taker submits tx with maker order + signature.
2. Payment processed via
3. License token moved to
4. On finalize, license transferred to taker; royalties routed.

4.3 Offer (BID)

• Symmetric to ASK; maker is buyer offering funds; escrow captures funds until seller accepts or offer expires.

4.4 Sublicensing

• Taker can mint controlled sublicenses via

4.5 Dispute & Override

• Any party may open a case;

5. Security & Governance

• RBAC for admin/issuer/validator roles via AccessControl.
• NonReentrant on all state-changing paths.
• Compliance Gate enforced pre/post trade (e.g., sanction checks).
• DAL Hooks for freeze/unfreeze & forced cancel/fill.
• Timeouts on escrows; auto-refund on expiry.
• Event Logs for every step -> audit index & AI anomaly detection.

6. Gas & Storage Strategy

• Use EIP-712 to avoid on-chain order storage (off-chain order book, on-chain settlement).
• Compact structs,
• Minimal writes: only record fills, cancels, disputes, and escrows.

7. Reference Contracts (Solidity)

7.1 EIP-712 Types & Order Hashing

// SPDX-License-Identifier: BUSL-1.1
pragma solidity ^0.8.24;

import {ECDSA} from "@openzeppelin/contracts/utils/cryptography/ECDSA.sol";

library OrderLib {
    bytes32 internal constant ORDER_TYPEHASH = keccak256(
        "Order(address maker,address asset,uint256 id,uint256 amount,address paymentToken,uint256 price,uint256 expiry,uint256 salt,bytes32 constraints,bytes32 jurisdiction,bytes32 side)"
    );

    struct Order {
        address maker;
        address asset;
        uint256 id;
        uint256 amount;
        address paymentToken;
        uint256 price;
        uint256 expiry;
        uint256 salt;
        bytes32 constraints;
        bytes32 jurisdiction;
        bytes32 side; // "ASK" or "OFFER"
    }

    function hash(Order memory o, bytes32 domainSeparator) internal pure returns (bytes32) {
        bytes32 structHash = keccak256(abi.encode(
            ORDER_TYPEHASH,
            o.maker, o.asset, o.id, o.amount, o.paymentToken, o.price, o.expiry, o.salt, o.constraints, o.jurisdiction, o.side
        ));
        return ECDSA.toTypedDataHash(domainSeparator, structHash);
    }
}

7.2 Escrow Vault (Custody + Timeouts + Freeze)

// SPDX-License-Identifier: BUSL-1.1
pragma solidity ^0.8.24;

import {IERC721} from "@openzeppelin/contracts/token/ERC721/IERC721.sol";
import {IERC1155} from "@openzeppelin/contracts/token/ERC1155/IERC1155.sol";
import {AccessControl} from "@openzeppelin/contracts/access/AccessControl.sol";
import {ReentrancyGuard} from "@openzeppelin/contracts/security/ReentrancyGuard.sol";

contract EscrowVault is AccessControl, ReentrancyGuard {
    bytes32 public constant MARKET_ROLE = keccak256("MARKET_ROLE");
    bytes32 public constant DAL_ROLE    = keccak256("DAL_ROLE");

    enum AssetKind { ERC721, ERC1155 }

    struct Escrow {
        address asset;
        uint256 id;
        uint256 amount;
        address seller;
        address buyer;
        uint64  deadline; // unix seconds
        bool    frozen;
        AssetKind kind;
    }

    mapping(bytes32 => Escrow) public escrows; // escrowId => Escrow

    event Opened(bytes32 indexed escrowId, address indexed asset, uint256 id, address seller, address buyer, uint64 deadline);
    event Finalized(bytes32 indexed escrowId, address to);
    event Canceled(bytes32 indexed escrowId);
    event Frozen(bytes32 indexed escrowId, bool frozen);

    constructor() { _grantRole(DEFAULT_ADMIN_ROLE, msg.sender); }

    function open(bytes32 escrowId, Escrow memory e) external onlyRole(MARKET_ROLE) nonReentrant {
        require(escrows[escrowId].seller == address(0), "ESCROW_EXISTS");
        escrows[escrowId] = e;
        // pull asset into vault
        if (e.kind == AssetKind.ERC721) {
            IERC721(e.asset).transferFrom(e.seller, address(this), e.id);
        } else {
            IERC1155(e.asset).safeTransferFrom(e.seller, address(this), e.id, e.amount, "");
        }
        emit Opened(escrowId, e.asset, e.id, e.seller, e.buyer, e.deadline);
    }

    function finalize(bytes32 escrowId) external onlyRole(MARKET_ROLE) nonReentrant {
        Escrow memory e = escrows[escrowId];
        require(!e.frozen && e.buyer != address(0), "FROZEN_OR_INVALID");
        if (e.kind == AssetKind.ERC721) {
            IERC721(e.asset).transferFrom(address(this), e.buyer, e.id);
        } else {
            IERC1155(e.asset).safeTransferFrom(address(this), e.buyer, e.id, e.amount, "");
        }
        delete escrows[escrowId];
        emit Finalized(escrowId, e.buyer);
    }

    function cancel(bytes32 escrowId) external onlyRole(MARKET_ROLE) nonReentrant {
        Escrow memory e = escrows[escrowId];
        // return to seller
        if (e.kind == AssetKind.ERC721) {
            IERC721(e.asset).transferFrom(address(this), e.seller, e.id);
        } else {
            IERC1155(e.asset).safeTransferFrom(address(this), e.seller, e.id, e.amount, "");
        }
        delete escrows[escrowId];
        emit Canceled(escrowId);
    }

    function setFrozen(bytes32 escrowId, bool f) external onlyRole(DAL_ROLE) { // DAL decision hook
        Escrow storage e = escrows[escrowId];
        require(e.seller != address(0), "NO_ESCROW");
        e.frozen = f;
        emit Frozen(escrowId, f);
    }
}

7.3 License Marketplace (Order Matching + DAL/TLAAS Gates)

// SPDX-License-Identifier: BUSL-1.1
pragma solidity ^0.8.24;

import {OrderLib} from "./OrderLib.sol";
import {ECDSA} from "@openzeppelin/contracts/utils/cryptography/ECDSA.sol";
import {AccessControl} from "@openzeppelin/contracts/access/AccessControl.sol";
import {ReentrancyGuard} from "@openzeppelin/contracts/security/ReentrancyGuard.sol";

interface IEscrowVault { function open(bytes32 id, Escrow memory e) external; }
interface IComplianceGate { function isAccountCompliant(address user) external view returns (bool); }
interface IPaymentOrchestrator { function payAndRoute(address token,uint256 amount,bytes32 op,bytes32 cat,bytes32 jur,address issuer) external; }

contract LicenseMarketplace is AccessControl, ReentrancyGuard {
    using ECDSA for bytes32;
    using OrderLib for OrderLib.Order;

    bytes32 public constant GOVERNANCE_ROLE = keccak256("GOVERNANCE_ROLE");
    bytes32 public DOMAIN_SEPARATOR;

    address public escrow;
    address public compliance;
    address public payments;

    mapping(bytes32 => bool) public filled;
    mapping(bytes32 => bool) public canceled;

    event Filled(bytes32 indexed orderHash, address indexed maker, address indexed taker, uint256 price, bytes32 escrowId);
    event Canceled(bytes32 indexed orderHash);

    constructor(bytes32 domainSeparator, address _escrow, address _compliance, address _payments) {
        _grantRole(DEFAULT_ADMIN_ROLE, msg.sender);
        _grantRole(GOVERNANCE_ROLE, msg.sender);
        DOMAIN_SEPARATOR = domainSeparator;
        escrow = _escrow;
        compliance = _compliance;
        payments = _payments;
    }

    function verify(OrderLib.Order memory o, bytes calldata sig) public view returns (bytes32 orderHash) {
        require(block.timestamp < o.expiry, "EXPIRED");
        orderHash = OrderLib.hash(o, DOMAIN_SEPARATOR);
        address signer = orderHash.recover(sig);
        require(signer == o.maker, "BAD_SIG");
    }

    function fill(OrderLib.Order memory o, bytes calldata sig, address issuer) external nonReentrant {
        bytes32 h = verify(o, sig);
        require(!filled[h] && !canceled[h], "FILLED_OR_CANCELED");
        require(IComplianceGate(compliance).isAccountCompliant(msg.sender) && IComplianceGate(compliance).isAccountCompliant(o.maker), "NON_COMPLIANT");

        // Payment + route royalties
        IPaymentOrchestrator(payments).payAndRoute(o.paymentToken, o.price, bytes32("TRANSFER"), o.constraints, o.jurisdiction, issuer);

        // Open escrow with token custody until finalize window lapses
        bytes32 escrowId = keccak256(abi.encode(h, msg.sender, block.timestamp));
        // NOTE: For brevity, Escrow struct import omitted in interface; use explicit call in production
        // IEscrowVault(escrow).open(escrowId, e);

        filled[h] = true;
        emit Filled(h, o.maker, msg.sender, o.price, escrowId);
    }

    function cancel(OrderLib.Order memory o) external {
        require(msg.sender == o.maker, "ONLY_MAKER");
        bytes32 h = OrderLib.hash(o, DOMAIN_SEPARATOR);
        canceled[h] = true;
        emit Canceled(h);
    }
}

7.4 Sublicense Module (Rights-Constrained Minting)

// SPDX-License-Identifier: BUSL-1.1
pragma solidity ^0.8.24;

import {AccessControl} from "@openzeppelin/contracts/access/AccessControl.sol";
import {ERC1155} from "@openzeppelin/contracts/token/ERC1155/ERC1155.sol";

contract SublicenseModule is ERC1155, AccessControl {
    bytes32 public constant MARKET_ROLE = keccak256("MARKET_ROLE");
    mapping(uint256 => bytes32) public rights; // rights flags per parent license id

    constructor(string memory uri_) ERC1155(uri_) { _grantRole(DEFAULT_ADMIN_ROLE, msg.sender); }

    function setRights(uint256 parentId, bytes32 flags) external onlyRole(MARKET_ROLE) { rights[parentId] = flags; }

    function mintSublicense(address to, uint256 parentId, uint256 amount) external onlyRole(MARKET_ROLE) {
        require((rights[parentId] & bytes32(uint256(1))) != 0, "NO_SUBLICENSE_RIGHT");
        _mint(to, parentId, amount, "");
    }
}

8. Front-End Architecture (React/TypeScript High-Level)

• State: Zustand/Redux for order cache; Wagmi/ethers for wallet.
• Modules:
• OrderBook (GraphQL) — fetch asks/bids
• TradeExecutor — crafts tx with signed orders
• EscrowTracker — monitors escrowId, timers, DAL freeze state
• DisputeCenter — opens cases via OverrideRouter
• ValidatorPanel — validator approvals (TLAAS)

TypeScript Interfaces

export type Order = {
  maker: `0x${string}`; asset: `0x${string}`; id: bigint; amount: bigint;
  paymentToken: `0x${string}`; price: bigint; expiry: number; salt: bigint;
  constraints: `0x${string}`; jurisdiction: `0x${string}`; side: "ASK"|"OFFER";
};

Fill Flow

// 1) fetch order + sig from indexer
// 2) onClick Buy -> call payments.payAndRoute -> open escrow -> wait finalize

9. Testing & Verification Plan

• Unit: Order hash, signature recovery, compliance gate, DAL freeze, escrow timeouts, payment integration.
• Integration: End-to-end buy-now & offer acceptance with simulated oracle confirmations.
• Property-Based: Fuzz amounts/expiries/salts; invariant checks (no asset loss).
• Security: Reentrancy, signature replay, order reuse, partial fills (if supported), griefing via freeze.

10. Deployment Checklist

• Configure DOMAIN_SEPARATOR (chain id/name).
• Set roles: MARKET_ROLE, DAL_ROLE, GOVERNANCE_ROLE.
• Link PaymentOrchestrator & RoyaltyRoutingEngine addresses.
• Register ComplianceGate (TLAAS) + OverrideRouter (DAL).
• Publish ABI + addresses + subgraph endpoint.

11. Next Steps

• Add auction module (English/Dutch) with time-based price curves.
• Implement partial fills & batch settles for gas efficiency.
• Ship full Graph subgraph schema & resolvers for analytics.

Next Article: CI/CD Pipeline — Automating Compilation, Testing and Deployment