TLaaS (LEX) — License Cryptographic Proof Anchoring & Audit Trail Mechanism

1. Purpose

Implement a verifiable cryptographic proof system for TLaaS (LEX) licenses, ensuring each license record is anchored to an immutable ledger and fully auditable. The mechanism must integrate with TLAAS (DLA) for compliance validation and DAL for governance oversight, while supporting both on-chain and off-chain audit queries.

2. Design Principles

• Proof Immutability: All proofs must be resistant to tampering via cryptographic hashing.
• Cross-Chain Anchoring: Support Ethereum mainnet, L2 rollups, and external notarization services.
• Efficient Storage: Store minimal proof data on-chain, with full audit logs on IPFS/Arweave.
• Time-Stamped Records: Use block timestamps and signed attestations for temporal verification.

3. Proof Structure

{
  "licenseId": "0x123...",
  "proofHash": "0xabc123...",
  "anchorTxHash": "0xdef456...",
  "blockNumber": 18000000,
  "timestamp": 1720560000,
  "auditorSignature": "0x987...",
  "dataRoot": "0xroot123..."
}

4. Solidity Anchoring Contract

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.24;

contract LicenseProofAnchor {
    struct Proof {
        bytes32 proofHash;
        bytes32 dataRoot;
        uint256 anchoredAt;
        address anchoredBy;
    }

    mapping(bytes32 => Proof) public proofs; // licenseId → Proof

    event ProofAnchored(bytes32 indexed licenseId, bytes32 proofHash, bytes32 dataRoot);

    function anchorProof(bytes32 licenseId, bytes32 proofHash, bytes32 dataRoot) external {
        require(proofs[licenseId].anchoredAt == 0, "Proof already exists");
        proofs[licenseId] = Proof(proofHash, dataRoot, block.timestamp, msg.sender);
        emit ProofAnchored(licenseId, proofHash, dataRoot);
    }

    function getProof(bytes32 licenseId) external view returns (Proof memory) {
        return proofs[licenseId];
    }
}

5. Off-Chain Audit Trail

• Hash Tree (Merkle Root): All license event logs for a given period hashed into a Merkle tree, with root anchored on-chain.
• Audit File Storage: Store detailed logs in IPFS/Arweave with CID recorded in governance-controlled registry.
• Third-Party Verification: Enable independent auditors to download logs, recompute hashes, and match on-chain anchors.

6. Proof Generation Workflow

1. Collect license metadata + compliance data.
2. Compute Keccak-256 hash of normalized JSON.
3. Aggregate into Merkle tree for batch anchoring.
4. Anchor Merkle root via
5. Upload full audit log to IPFS/Arweave.

7. Integration with TLAAS & DAL

• TLAAS (DLA): Consumes anchored proofs to verify authenticity before license enforcement.
• DAL: Reviews and approves periodic audit reports.

8. Operational Runbook

• Anchor proofs in real time or in hourly/daily batches.
• Maintain redundant IPFS pinning and Arweave backups.
• Conduct quarterly verification drills with independent auditors.

9. Acceptance Criteria

• 100% of issued licenses have valid on-chain proof.
• All proofs independently verifiable.
• Zero mismatches between on-chain anchor and off-chain audit data.

Next Article: Decentralized License Revocation & Dispute Resolution Protocol