Mixed Identifier Schemes in Textile Supply Chains
This use case demonstrates how different identifier schemes — both registry-managed (e.g., GS1 GTINs, national business registry numbers) and self-issued (e.g., Decentralized Identifiers/DIDs) — can work together seamlessly in textile supply chains through the UNTP Identity Resolver, enabling interoperability without requiring actors to change their existing identification systems.
This is not a theoretical concept — the UNTP Identity Resolver is a core part of the UNTP specification and provides standardized, proven mechanisms for mixed identifier usage. The specification includes detailed requirements, examples, and implementation guidance that make this achievable in practice.
What are Mixed Identifier Schemes?
Textile supply chains involve many actors using different identifier systems, and the UNTP approach recognizes this reality:
- Registry-managed identifiers — Issued by authoritative registers (e.g., GS1 for products, national business registries for companies, certification scheme registries for facilities). These leverage existing, trusted identification systems that many actors already use.
- Self-issued identifiers — Created and controlled by entities themselves, typically using Decentralized Identifiers (DIDs). These provide autonomy and flexibility for actors who don't want to depend on central registries, or who need cost-effective solutions.
The key insight is that both types can work together — you don't need to choose one or the other. The UNTP Identity Resolver provides the standardized framework that makes this interoperability possible.
The UNTP Identity Resolver enables both types to participate in a consistent Discover-Resolve-Verify (D-R-V) workflow, allowing different identifier schemes to interoperate while maintaining their unique governance models. This is a proven, standardized approach that has been designed specifically to address the challenge of mixed identifier usage in global supply chains.
Why This Matters
- Preserve Existing Investments — Actors can continue using their current identifier systems (GS1, national registries, internal IDs) without migration costs or disruption.
- Interoperability Without Centralization — Different identifier schemes can work together without requiring a single, centralized identifier authority.
- Flexibility for Different Actors — Large brands can use registry-managed identifiers, while smaller suppliers can use self-issued DIDs, and both can participate in the same supply chain.
- Global Supply Chain Support — Accommodates diverse identification practices across different countries, sectors, and business models.
- Progressive Adoption — Actors can start with simple self-issued identifiers and later adopt registry-managed schemes, or vice versa. The UNTP specification supports this flexibility, making it easy to evolve your identifier strategy over time.
Current Gaps
Traditional traceability systems often require all actors to use the same identifier scheme, creating barriers:
Single-Scheme Lock-in
- Forced standardization — Systems typically require all participants to adopt a single identifier scheme (e.g., all GS1, or all proprietary), forcing actors to abandon existing systems or creating exclusion barriers.
- Migration costs — Switching identifier schemes requires updating databases, labels, systems, and training, which is expensive and disruptive.
- Geographic limitations — Different regions use different identifier schemes (e.g., GS1 in some markets, national registries in others), making global traceability difficult.
Lack of Interoperability
- Siloed systems — Different identifier schemes operate in isolation, making it impossible to link data across schemes or verify claims that span multiple identifier types.
- No common resolution mechanism — Each identifier scheme has its own resolution method, requiring custom integration for each scheme used in a supply chain.
Limited Flexibility
- All-or-nothing approaches — Systems typically force either full registry dependency or complete self-management, with no middle ground for actors with varying needs and capabilities.
Actors
The following actors participate in mixed identifier scheme scenarios:
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Registry Operators — Organizations that issue and manage registry-managed identifiers (e.g., GS1, national business registries, certification scheme registries). They provide authoritative identifier resolution services. See the Registers register for registered identity registers supporting the Textiles Extension.
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Large Brands / Retailers — Often use registry-managed identifiers (e.g., GS1 GTINs) for products and may require suppliers to use specific identifier schemes. They need to verify and link data from multiple identifier types. See the Industry Actors register for registered industry organizations.
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Manufacturers / Processors — May use registry-managed identifiers for products (e.g., GS1) but self-issued identifiers for internal batches or facilities. Need flexibility to work with different identifier types. See the Industry Actors register for registered industry organizations.
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Small Suppliers / Farms — Often lack resources for registry-managed identifiers and prefer self-issued DIDs for cost and autonomy. Must still participate in supply chains with larger actors using different schemes. See the Industry Actors register for registered industry organizations.
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Certifiers / Auditors — Need to verify and link facility and product identifiers across different schemes to validate claims and certifications. See the Certifiers register for registered certifiers supporting the Textiles Extension.
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Software Providers — Build systems that must support multiple identifier types and provide resolution services for both registry-managed and self-issued identifiers. See the Software register for registered software solutions supporting the Textiles Extension.
UNTP Mapping
The UNTP Identity Resolver specification provides a unified framework for both identifier classes. This specification is part of the core UNTP standard and has been designed to work with any identifier scheme, making mixed identifier usage not just possible, but straightforward to implement:
| Identifier Type | Characteristics | UNTP Support |
|---|---|---|
| Registry-managed identifiers | Issued by authoritative register (GS1, national registries, etc.) | Resolver templates from registry, registry as source of truth for discovery and verification |
| Self-issued identifiers (DIDs) | Created and controlled by entity itself | DID resolution via DID methods, DID Document exposes service endpoints and cryptographic material |
Both types support the Discover-Resolve-Verify (D-R-V) workflow defined in the UNTP Identity Resolver specification:
- Discoverable — Identifiers can be retrieved from data carriers (barcodes, QR codes, RFID) or documents and normalized to consistent URI representations. The specification provides clear guidance on how to normalize identifiers from different schemes.
- Resolvable — Identifiers can be dereferenced to obtain structured data that expose related UNTP credentials and records. The resolution process is standardized and well-documented in the UNTP Identity Resolver specification.
- Verifiable — Claims made by the identifier's controller can be distinguished from third-party statements using cryptographic proofs. This verification process works consistently across all identifier types.
The UNTP specification ensures that regardless of which identifier scheme you use, the same discovery, resolution, and verification processes apply, making interoperability achievable in practice.
Data Flow
A typical textile supply chain using mixed identifiers:
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Facility Registration — A cotton farm uses a self-issued identifier for its facility, while a large spinning mill uses a registry-managed identifier from a national business registry.
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Product Identification — The farm creates a Digital Product Passport for a cotton batch using its self-issued facility identifier. The spinning mill receives the cotton and creates yarn batches using GS1 GTINs (registry-managed identifiers).
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Traceability Events — When the mill ships yarn to a fabric manufacturer, a Digital Traceability Event links:
- Input: The farm's self-issued identified cotton batch
- Output: The mill's registry-managed identified yarn batch
- Facilities: Both the self-issued identified farm and registry-managed identified mill
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Verification — A brand receiving the final product can:
- Resolve the registry-managed identifier to find the yarn batch passport
- Follow traceability events back to the farm's self-issued identified cotton
- Verify both identifiers through their respective resolution mechanisms (as defined in the UNTP Identity Resolver specification)
- Build a complete provenance chain despite different identifier schemes
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Cross-Scheme Linking — The UNTP Identity Resolver enables seamless linking between:
- Registry-managed facility identifiers and self-issued product identifiers
- Registry-managed product identifiers and self-issued batch identifiers
- National business registry identifiers and certification scheme identifiers
This cross-scheme linking is a core feature of the UNTP specification, not an add-on or workaround. The specification provides standardized mechanisms for linking identifiers across different schemes, ensuring that complete provenance chains can be built regardless of which identifier types are used at each stage.
Benefits
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Scheme-agnostic interoperability — Different identifier schemes can coexist and interoperate without requiring actors to change their existing systems. This is a core feature of the UNTP Identity Resolver specification, not an optional add-on.
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Reduced barriers to entry — Small suppliers can participate using self-issued DIDs without the cost and complexity of registry-managed identifiers. The specification provides clear guidance on implementing self-issued identifiers.
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Preserved investments — Actors can continue using their existing identifier systems (GS1, national registries, internal schemes) while gaining interoperability benefits. The UNTP approach builds on existing systems rather than replacing them.
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Global supply chain support — Accommodates diverse identification practices across different countries, sectors, and business models. The specification is designed to work with identifier schemes from around the world.
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Progressive adoption — Actors can start simple (self-issued) and adopt registry schemes later, or vice versa, without breaking existing integrations. The specification supports this flexibility.
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Flexible governance — Each identifier type maintains its own governance model (centralized for registries, decentralized for DIDs) while participating in a unified resolution framework. This is built into the specification's design.
Technical Guidance
The UNTP Identity Resolver specification provides comprehensive technical guidance for implementing mixed identifier schemes. The specification is designed to be practical and implementable, with clear requirements and examples.
UNTP Identity Resolver Foundations
The UNTP Identity Resolver specification defines how both registry-managed and self-issued identifiers can participate in a consistent discovery and verification workflow. The specification is part of the core UNTP standard and has been designed with real-world implementation in mind.
Key principles that make this achievable:
- No replacement of existing schemes — UNTP builds upon existing identifier systems rather than replacing them. You don't need to abandon your current identifiers.
- Consistent URI representation — The specification provides clear conventions for normalizing all identifiers to consistent formats, making cross-scheme linking straightforward. See the Linked Data Needs section of the specification for detailed guidance.
- Unified resolution interface — Both identifier types support the Discover-Resolve-Verify workflow. While the implementation details differ (registry templates vs DID methods), the overall process is consistent and well-documented.
Identifier Representation Conventions
The UNTP Identity Resolver specification defines clear conventions for consistent identifier representation. These conventions ensure that identifiers from different schemes can be normalized and linked reliably.
The specification covers:
- Registry-Managed Identifiers — How to represent identifiers from authoritative registers (GS1, national registries, etc.). See the Registry-Managed Identifiers section for detailed guidance.
- Self-Issued Identifiers (DIDs) — How to represent self-issued identifiers following W3C DID standards. See the Self-Issued Identifiers section for detailed guidance.
For complete technical details on identifier formats, normalization, and representation conventions, refer to the Linked Data Needs section of the UNTP Identity Resolver specification.
Discover-Resolve-Verify Workflow
The UNTP Identity Resolver specification defines a standardized Discover-Resolve-Verify (D-R-V) workflow that works for both identifier types. This workflow ensures that regardless of which identifier scheme is used, the same discovery, resolution, and verification processes apply:
Discover
- Registry-managed: Identifiers are discovered from data carriers (barcodes, QR codes, RFID) and normalized to consistent representations. The Discoverable section for Registry-Managed Identifiers provides detailed guidance on data carrier support and normalization.
- Self-issued: Self-issued identifiers are discovered from data carriers or documents. The Discoverable section for Self-Issued Identifiers covers discovery processes.
Resolve
- Registry-managed: Identifiers are resolved through registry-provided resolver templates, which return structured data containing references to related UNTP credentials and records. The Resolvable section for Registry-Managed Identifiers explains the resolution process.
- Self-issued: Self-issued identifiers are resolved through standardized methods to obtain structured data containing service endpoints and verification material. The Resolvable section for Self-Issued Identifiers covers resolution processes.
Verify
- Both types: Verification uses cryptographic proofs to distinguish claims made by the identifier's controller from third-party statements. The Verifiable (shared) section explains how verification works consistently across both identifier classes.
For complete technical details on the Discover-Resolve-Verify workflow, refer to the UNTP Identity Resolver specification.
Implementation Patterns
Pattern 1: Registry Products, Self-Issued Facilities
A large brand uses GS1 GTINs for products but a small supplier uses a DID for its facility:
Pattern 2: Mixed Product Identifiers
Different actors in the same supply chain use different product identifier schemes:
Identity & Credential Types
| Entity / Object | Identifier Type Examples | Resolution Method |
|---|---|---|
| Facility | Registry-managed or self-issued identifiers | Registry resolver templates or self-issued resolution methods |
| Product / Batch | Registry-managed, self-issued, or internal identifiers | Scheme-specific resolution, self-issued resolution, or internal resolver services |
| Digital Product Passport | References product identifier (any type) | Resolves product identifier, then follows links to DPP |
| Digital Facility Record | References facility identifier (any type) | Resolves facility identifier, then follows links to DFR |
| Digital Conformity Credential | References facility/product identifiers (any type) | Resolves identifiers, then verifies credential claims |
For detailed information on identifier formats and examples, refer to the UNTP Identity Resolver specification.
Implementation & Integration Guidelines
The UNTP Identity Resolver specification provides detailed implementation guidance. Key considerations for successful implementation:
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Use consistent identifier normalization — The specification provides clear conventions for normalizing identifiers to consistent formats. See the Linked Data Needs section for detailed specifications.
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Support multiple resolution methods — The specification defines how to implement resolvers for both registry-managed identifiers (via registry templates) and self-issued identifiers (via DID methods). Both approaches are well-documented and achievable.
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Maintain identifier scheme metadata — Include identifier scheme information in credentials and records to enable appropriate resolution method selection. The specification provides guidance on how to structure this metadata.
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Enable cross-scheme linking — The specification is designed to support cross-scheme linking. Design traceability events and product passports to reference identifiers from different schemes, enabling provenance chains that span multiple identifier types.
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Support progressive adoption — The UNTP approach allows actors to start with simple self-issued identifiers and later adopt registry schemes (or vice versa) without breaking existing links. This flexibility is built into the specification.
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Implement fallback resolution — The specification provides mechanisms for handling resolution failures and fallback scenarios, ensuring robust operation in real-world conditions.
Sample Data
Example identifier resolution scenarios and data structures will be added here as the extension is developed. This section will include:
- Sample registry-managed identifier resolution (GS1 GTIN to linkset)
- Sample self-issued identifier resolution (DID to DID Document with linkset)
- Sample cross-scheme traceability event linking registry and self-issued identifiers
- Complete example showing mixed identifier usage across a textile supply chain
For now, refer to the UNTP Identity Resolver specification for detailed resolution mechanisms, including:
- Registry-Managed Identifiers examples
- Self-Issued Identifiers examples
- Registry-Managed and Self-Issued Example Comparison
The specification includes practical examples showing how both identifier types work in practice, making implementation achievable.
Conformance & Validation
As the extension is developed, test suites and methods of technical validation will be provided.
The UNTP Identity Resolver specification includes formal requirements that ensure consistent implementation. Ensure all identifier resolutions follow UNTP conventions:
- Identifier normalization — All identifiers are normalized to consistent formats per the Linked Data Needs conventions in the specification.
- Resolution compliance — Registry-managed identifiers resolve via registry templates; self-issued identifiers resolve via DID methods, as defined in the specification.
- Resolution response structure — Resolution responses conform to standardized structures as specified in the Resolvable sections of the specification.
- Cross-scheme linking — Traceability events and credentials correctly reference identifiers from different schemes and maintain referential integrity, as supported by the specification's design.
Summary
The UNTP Identity Resolver enables mixed identifier schemes to work together seamlessly in textile supply chains, allowing actors to use their preferred identifier types (registry-managed or self-issued) while maintaining interoperability.
Key Takeaways
- Registry-managed identifiers (GS1, national registries) and self-issued identifiers (DIDs) can coexist and interoperate through the UNTP Identity Resolver.
- Both identifier types support the Discover-Resolve-Verify (D-R-V) workflow, though implementation differs.
- Actors can preserve existing identifier investments while gaining interoperability benefits.
- Small suppliers can use self-issued DIDs without registry costs, while large brands can use registry-managed schemes.
- Cross-scheme linking enables complete provenance chains even when different actors use different identifier types.
The UNTP Identity Resolver specification provides comprehensive technical documentation, including:
- Detailed requirements and formal specifications
- Practical examples for both identifier types
- Implementation guidance for registry-managed and self-issued identifiers
- Clear conventions for identifier representation and normalization
For implementation guidance, see the Technical Guidance section above, or refer directly to the UNTP Identity Resolver specification for complete technical details. The specification is designed to be implementable and includes all the information needed to successfully support mixed identifier schemes in textile supply chains.