WellData Implementation Guide
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Research Data Overview

Research Data Exchange Overview

The WellData project facilitates the secure and ethical exchange of well-being data for research purposes through a delegated consent model. This approach balances the needs of research with strong user privacy protections and consent management.

                          │
                          │
                          │
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     Trusts       ┌─────────────┐        Qualifies
       ┌──────────►Trusted Party│─────────────┐
       │          └─────────────┘             │
       │                                      │
       │                                      │
   ┌──────┐                              ┌────▼─────┐
   │ User │─────► Consent + Data ◄───────│Researcher│
   └──────┘               │              └──────────┘
       │                  │
       │                  │
 ┌─────────────┐     ┌──────────┐
 │ Application │     │Data Store│
 └─────────────┘     └──────────┘

                          │
Private space             │          Anonymous data
                          │
                          │

Key Principles

  • Delegated Consent: Users delegate authorization decisions to a Trusted Third Party (TTP) rather than directly to individual researchers
  • Preference-Based Consent: User consent includes specific preferences regarding data usage
  • Data Minimization: Only necessary data is shared according to consent parameters
  • Qualified Access: Researchers must meet TTP-defined qualification standards
  • Revocable Consent: Users maintain the right to revoke consent at any time
  • Trust Network: Trust relationships are managed through the NUTS network and Verifiable Credentials

Process Flow

  • User completes a questionnaire or task generating well-being data
  • User provides consent to the TTP with specific preferences:
    • Research purpose limitations
    • Data type restrictions
    • Time limitations
    • Other user-defined preferences
  • Data and consent are stored together in the data store/data station

2. Researcher Qualification

  • TTP establishes qualification standards for researchers
  • Researchers apply for qualification, providing:
    • Research institution credentials
    • Research purpose documentation
    • Ethics committee approvals (where applicable)
    • Data handling protocols
  • TTP evaluates and qualifies researchers according to established criteria

3. Access Permission Management

  • Qualified researchers request data access from the TTP
  • TTP evaluates whether the request matches user consent preferences
  • Upon approval, TTP issues permissions as Verifiable Credentials
  • Researchers present these credentials as Verifiable Presentations when accessing data

4. Data Query and Response

  • Researchers query the data station with their permissions
  • Data station validates:
    • Researcher identity and qualifications
    • Permission validity and scope
    • Matching with stored user consent
  • Data is anonymized before release
  • All access is logged for audit purposes
  • Users can view and manage their active consents through the originating application's interface
  • Users can modify or revoke consent at any time through the same application that collected the consent
  • Consent changes are propagated to affect future data access
  • The data store respects consent revocation immediately upon receiving the update

Trust Management with NUTS

The WellData project leverages the NUTS network as the foundation for trust management between all participants in the research data ecosystem. NUTS is an open-source trust network that facilitates secure data exchange in healthcare while maintaining user privacy and sovereignty.

NUTS Core Principles in WellData

  • Decentralized Trust: No central authority controls the entire network
  • User Sovereignty: Users maintain control over their data and consent
  • Cryptographic Verification: All trust relationships can be cryptographically verified
  • Standardized Protocols: Ensuring interoperability across the ecosystem

Trust Flow Implementation

  1. User to TTP Trust: Users provide consent that is stored with their data in a predefined format, authorizing the TTP to manage research data access
  2. TTP to Researcher Trust: TTPs issue VCs to qualified researchers defining their access rights
  3. Data Station to TTP Trust: Data stations verify the trust chain from researchers through the TTP to user consent
  4. Revocation Management: Consent can be revoked through the originating application, while VCs can be revoked through the NUTS network revocation registry

Each participant in the ecosystem maintains a digital wallet that stores their VCs and manages trust relationships according to the NUTS protocols.

Technical Implementation

Consent is stored together with the data in a predefined JSON format with the following key components:

{
  "consentId": "<unique-consent-id>",
  "dataSubject": "<User-DID>",
  "trustedParty": "<TTP-DID>",
  "creationDate": "<ISO-8601-timestamp>",
  "expirationDate": "<ISO-8601-timestamp>",
  "consentPreferences": {
    "purposeRestrictions": ["medical_research", "public_health", ...],
    "dataTypes": ["questionnaire_responses", "activity_data", ...],
    "minimumAnonymizationLevel": "k-anonymity-5",
    "additionalConditions": [...]
  },
  "dataLocation": "<data-reference-or-container>",
  "revocationStatus": "active"
}

Data Station Requirements

  • Secure storage with access controls
  • Query processing capabilities with consent validation
  • Anonymization techniques (k-anonymity, differential privacy)
  • Comprehensive logging and auditing
  • User notification mechanisms

TTP Qualification Issuance

The TTP issues Verifiable Credentials to qualified researchers through the NUTS network containing:

{
  "@context": [
    "https://www.w3.org/2018/credentials/v1",
    "https://nuts.nl/credentials/v1"
  ],
  "type": ["VerifiableCredential", "ResearcherQualification"],
  "issuer": "<TTP-DID>",
  "issuanceDate": "<ISO-8601-timestamp>",
  "expirationDate": "<ISO-8601-timestamp>",
  "credentialSubject": {
    "id": "<Researcher-DID>",
    "qualificationLevel": "<level>",
    "allowedPurposes": ["purpose1", "purpose2", ...],
    "restrictions": {
      "maxQueryFrequency": "<value>",
      "dataRetentionPolicy": "<policy>"
    },
    "evidenceDocuments": ["<reference1>", "<reference2>", ...],
    "nutsRegistryEntry": "<registry-identifier>"
  }
}

Privacy and Security Considerations

Anonymization

  • Data is anonymized before being shared with researchers
  • Techniques include:
    • k-anonymity
    • Differential privacy
    • Data aggregation
    • Removal of identifiers

Audit Trail

  • All data access is logged with:
    • Researcher identifier
    • Query parameters
    • Timestamp
    • Purpose declaration
    • Data returned (metadata only)

Transparency

  • Users can view:
    • Active consents
    • Data access logs
    • Research outcomes (where applicable)
    • TTP qualification standards

Integration with the NUTS Network

For research data, the applications write data and consent directly to the data store, bypassing the SOLID/POD ecosystem. This creates a separate flow specifically optimized for research data management:

Direct Data Store Approach

  • Research data is written directly to the data store by applications
  • Consent is stored alongside the data in the data store
  • The data store maintains separation from the healthcare data in SOLID pods
  • This approach optimizes for research-specific requirements including anonymization and aggregation

NUTS Network Integration

  • DIDs (Decentralized Identifiers) and VCs follow NUTS specifications
  • Trust relationships are registered and discoverable through the NUTS registry
  • Credential exchange happens through NUTS wallets for all participants
  • Revocation management uses the NUTS revocation service
  • Audit logging can be anchored to the NUTS network for non-repudiation

Compliance Requirements

  • GDPR Article 9 (processing of special category data)
  • GDPR Articles 6 & 7 (lawfulness and conditions of consent)
  • GDPR Article 89 (research exemptions and safeguards)
  • Local research ethics requirements
  • Medical research standards where applicable