Registry Record Creation
How verified MassIDs become tamper-evident, publicly verifiable registry records — from metadata creation through durable public storage to issuance on the public registry.
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From verified data to public registry records
After a MassID passes methodology verification, it is issued as a registry record — transformed from a platform-held verified record into a tamper-evident, publicly verifiable entry on the public registry. Issuance creates a publicly verifiable link between the physical recycling work and its digital representation in the registry.
Registry issuance is the bridge between the digital MRV (dMRV) verification process and the credit lifecycle that ultimately produces tradeable environmental credits.
The registry-record creation process
1. Verification complete
The MassID has passed all methodology checks. Its material type, weight, and chain of custody are validated, and all compliance conditions defined by the applicable methodology are satisfied. The MassID is marked as ready for registry recording.
2. Metadata creation
Structured metadata is compiled for the MassID. This metadata captures the complete provenance record:
| Field | Description |
|---|---|
| Material type | The waste material classification (e.g., clear glass, plastic, organic food waste) |
| Weight | The verified weight in kilograms |
| Chain of custody | Every participant who handled the material, identified by a non-reversible participant hash and role |
| Timestamps | When each event in the chain of custody occurred |
This metadata becomes the content-addressed description referenced by the MassID's registry record. The methodology that verified the material — its name, version, and a link to the published specification — and a reference to the verification are pinned on the certificate issued from this MassID, which references the MassID by token id and IPFS URI. The rule results, the review decisions and their inputs stay platform-held and are reflected in the Carrot Registry.
3. Decentralized storage
The compiled metadata is uploaded to IPFS (InterPlanetary File System), producing a content-addressed URI. This URI is unique to the metadata content — any change to the data would produce a different URI, making the stored record tamper-evident.
The IPFS URI is then referenced by the on-chain registry record, linking the lightweight blockchain entry to the full metadata stored in decentralized storage.
4. Registry record creation
The MassID is recorded on-chain as a non-transferable registry record held by the Vault contract. The implementation uses ERC-721, while the public model is the MassID record itself. The creation transaction records the IPFS metadata URI on-chain, associating the registry entry with its provenance data. Because the metadata is content-addressed, that association is tamper-evident: any later change to the on-chain reference emits a public event, so the record is auditable rather than silently editable.
A registry record can also be revoked. A network operator can revoke a MassID when its underlying data is later found to be invalid, which replaces its metadata reference with a revocation record and removes the token from the Vault. Revocation is blocked once credits from the MassID's certificates have been sold, and it does not cascade — the linked certificates have to be revoked first.
Because MassID records are non-transferable, they cannot be traded or moved between accounts. This ensures the provenance chain remains intact and prevents speculative activity on verification records.
5. Record linking
The platform updates its internal records to connect the verified MassID with its on-chain registry-record ID. This linkage ensures that the platform, the blockchain, and the Carrot Registry all reference the same underlying data — creating a consistent, auditable record across systems.
What happens next
Recorded MassIDs are the foundation upon which the rest of the credit lifecycle is built. Once a MassID exists on the public registry:
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Certificates are generated — When MassIDs pass methodology verification at a facility accredited by independent third-party auditors, certificates (RecycledID or GasID) are recorded, referencing the underlying MassID records as proof of the physical work performed.
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Credits are issued — Each certificate generates fungible credits (TRC or TCC), using the unit defined by its methodology. These credits are the tradeable units that buyers purchase to meet their environmental commitments.
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Full traceability is established — From a retired credit, any party can trace back through the certificate, to the recorded MassID, to the IPFS metadata, and ultimately to the specific waste batches and supply chain participants that performed the work. This traceability is publicly verifiable through the Carrot Registry or any blockchain block explorer (e.g. PolygonScan).
Related pages
- Credit Lifecycle — The MassID, Certificate, and Credit lifecycle and relationships
- Smart Contracts — The on-chain infrastructure that manages registry-record creation and custody
- MassIDs — The foundational data unit representing verified waste batches