Owner: CrownThrive, LLC Date: 2025-08-08 Classification: Internal — License Token Data Structures, Metadata Standards, and On-Chain Verification
1. Purpose
This document defines the schema, metadata fields, and token standards for representing licenses within the CHLOM License Exchange. The goal is to create a universal, interoperable NFT/SFT structure that supports verifiable licensing, dynamic compliance updates, and multi-jurisdictional validation.
2. Token Standards
- Format: ERC-721 for unique licenses; ERC-1155 for semi-fungible licenses (e.g., identical usage rights for multiple holders).
- On-Chain Metadata: Minimal critical fields stored directly on-chain.
- Off-Chain Metadata: Extended license data stored via IPFS/Arweave, hashed for integrity.
- Upgradeability: DAO-controlled metadata schema evolution.
3. Core Metadata Fields
On-Chain Fields:
- issuer_id
- license_type
- jurisdiction
- expiry_date
- zk_proof_refs
Off-Chain Fields:
- terms_url
- compliance_score
- transferability
- audit_history
- extensions
4. License Issuance Workflow
- Issuer Authentication: Verify DAO-approved issuer credentials.
- Metadata Compilation: Collect required on-chain and off-chain fields.
- ZKP Generation: Generate zero-knowledge proof of license validity.
- Token Minting: Mint ERC-721/1155 token with on-chain metadata.
- Proof Anchoring: Store proof hash and metadata signature on-chain.
- Distribution: Deliver token to recipient wallet with compliance hooks.
5. Security & Integrity
- Proof Anchoring: All license claims linked to verifiable proofs.
- Mutability Controls: On-chain metadata immutable except via DAO-governed upgrade.
- Encryption: Sensitive off-chain metadata encrypted and key-shared with authorized parties.
- Double-Mint Prevention: Smart contract checks to ensure unique license issuance.
6. Developer Notes
- Languages: Solidity, Rust (Substrate pallet for NFT module).
- Interoperability: Support for EIP-2981 (royalty standard) and EIP-712 (typed structured data signing).
- Example Schema (Solidity Struct):
struct LicenseMetadata {
string issuerId;
string licenseType;
string jurisdiction;
uint256 expiryDate;
string[] zkProofRefs;
}
7. Extended Capabilities (Optional)
- Advanced Tokenomics Hooks: License tokens can yield staking rewards when compliance score stays above threshold.
- Cultural Preservation Metadata: Tags for cultural heritage licenses with special DAO governance protections.
- Reinvestment Strategies: Penalty fees from non-compliance reinvested into ecosystem development funds.
This specification ensures CHLOM License Exchange licenses are universally interoperable, verifiable, and resilient against fraud, while allowing for future-proof upgrades through DAO governance.