Transferable Records

Verifiable vs Transferable

Most trade documents — commercial invoices, packing lists, certificates of origin — need to be verifiable: a receiving party must be able to confirm who issued the document and that it has not been tampered with. A W3C Verifiable Credential achieves this through cryptographic signatures.

Some trade documents go further. A bill of lading, for example, is not just a record of shipment — it is a document of title. Whoever holds the original bill of lading has the right to claim the goods. This means the document must satisfy requirements that ordinary verifiable credentials do not:

• Singularity — there can only be one authoritative original, not copies.
• Exclusive control — only one party controls the document at any given time.
• Transferability — control must be transferable from one party to another in a way that is provable and irreversible.
• Surrender — the document must be consumable (surrendered) to release the goods, after which no further transfers are valid.

These requirements apply to any document that confers rights or title: bills of lading, warehouse receipts, promissory notes, and similar instruments.

UNCITRAL MLETR

The UNCITRAL Model Law on Electronic Transferable Records (MLETR)  provides the legal framework for digital equivalents of paper-based transferable documents. Adopted in 2017, MLETR establishes that an electronic record can have the same legal effect as a paper document if a reliable method is used to:

• Identify the electronic record as the authoritative original.
• Render it capable of being subject to exclusive control.
• Retain its integrity from the time of creation.
• Allow the person in control to demonstrate that control to others.

MLETR is technology-neutral — it does not prescribe how these requirements are met, only that they must be. As of 2025, MLETR-aligned legislation has been adopted or is in progress in multiple jurisdictions, including Singapore (Electronic Transactions Act), the United Kingdom (Electronic Trade Documents Act 2023), and others.

Current Approaches: Blockchain Platforms

The most common approach to satisfying MLETR’s singularity and exclusive control requirements is to use a blockchain or distributed ledger as the authoritative record of who currently controls a transferable document. Platforms such as Singapore’s TradeTrust, and various commercial eBL providers, use ledger-based registries to track title transfers.

This works within a single platform, but creates a fundamental problem for global trade: cross-ledger interoperability. A consignor and consignee cannot always agree on which ledger to use before shipping, particularly when:

• Different jurisdictions favour different platforms.
• Trading partners have existing relationships with different providers.
• New counterparties are encountered on every voyage.
• Smaller traders cannot afford to integrate with multiple platforms.

The result is the same fragmentation problem that has limited hub-and-pipe EDI models — participants must be on the same network to transact, which caps adoption.

An Emerging Alternative: Protocol-Based Approaches

Recent work on cryptographic event log (CEL) DID methods — such as did:webvh (did:web with verifiable history) and did:cel — suggests a potential protocol-based alternative to platform-based ledger solutions.

The core idea is to represent the transferable record itself as a DID whose append-only, cryptographically verifiable event log constitutes the authoritative record of control:

• The DID identifies the instrument (e.g., a specific bill of lading), not a person or organization.
• Control transfer is an event appended to the log, signed by the current controller, cryptographically linked to the previous event.
• Current controller is determined by resolving the DID and reading the latest valid control event — no registry lookup beyond DID resolution is required.
• Surrender is a terminal event that freezes the chain, after which no further transfers are valid.

This approach addresses the MLETR requirements directly:

Two additional mechanisms strengthen the model:

Witnesses. Control transfer events can be countersigned by relevant parties (carrier, bank, port authority) — still decentralized, but socially anchored. This reduces disputes about “who controlled it when” and provides finality guarantees without a central registry.

Heartbeats. Borrowing from the did:cel specification, the current controller periodically signs a heartbeat event to prove continued possession. This adds liveness semantics — if the heartbeat expires, control can revert to a defined fallback (issuer, escrow, legal process). This solves the practical problem of lost keys or abandoned instruments, and maps closely to how physical possession works.

Why This Matters for UNVTD

A protocol-based approach to transferable records would mean that any party capable of resolving a DID and verifying signatures can participate in title transfer — without needing to join a specific platform or ledger. This aligns directly with UNVTD’s architectural principle that no shared infrastructure should be required to exchange trade documents.

This area is still emerging. UNVTD will track developments in CEL-based DID methods and witnessed transfer protocols as potential foundations for transferable document types such as bills of lading and warehouse receipts.