WP3 - Technology and Standards (WE BUILD Consortium)

The WP3 Technology and Standards Group is responsible for defining the common standards for the WE BUILD consortium, which is piloting the EU Digital Identity Wallet (EUDIW). This work package focuses on the banking and payments sectors, covering both consumer and corporate segments.

The goal of this repository is to provide a central place for technical specifications, sequence diagrams, and implementation examples that enable interoperable use of the EUDI Wallet in WP3 usecases and scenarios.

Directory Structure

.
├── PA1/                                # UseCase PA1 (Consumer banking)
│   ├── Scenario 4/                     # Specific issuance scenario 4
│   ├── examples/                       # Issuance examples
│   └── issuance/                       # Sequence diagrams for issuance
├── PA2/                                # Pilot Application 2 (Presentation)
│   ├── PA2 A_1/                        # Presentation Flows
│   │   └── sequence/
│   └── PA2 A_2/                        # Extended Presentation (SUA)
│       ├── attestations/               # SUA and other attestation examples
│       ├── examples/
│       │   ├── DC_API_examples/        # API request examples (JSON)
│       │   └── Deeplinks/
│       └── sequence/
└── general/                            # Common assets and examples
    ├── examples/
    │   ├── attestation/                # Example SD-JWT and W3C VC attestations
    │   │   ├── IBAN Confirmation/
    │   │   ├── IBAN SUA/
    │   │   └── SUA/
    │   └── metadata/                   # Metadata examples (Issuer/Verifier)
    └── sequence/                       # Shared sequence diagrams

Folder Descriptions

PA1/ - Issuance

Focuses on the Credential Issuance phase within the EUDIW ecosystem, specifically for banking-related credentials.

• Scenario 4/: Specific issuance scenario documentation.
• issuance/: PlantUML diagrams for various issuance business flows:
  • Authorized Code Flow: Standard OID4VCI issuance.
  • Pre-authorized Code Flow: Simplified issuance for known users.
  • Credential Refresh: Mechanisms for updating existing credentials.
  • General Issuance Business Flow: End-to-end overview of the issuance process.

PA2/ - Presentation

Focuses on the Presentation phase and the interaction between the EUDI Wallet and Relying Parties (RPs) or Data Providers.

• PA2 A_1/: Technical diagrams for Digital Credentials (DC) API and Deep-link based presentation flows.
• PA2 A_2/:
  • examples/DC_API_examples/: JSON examples for signed and unsigned credential requests.
  • attestations/: Examples of Signed User Allegations (SUA) for IBAN and other financial attributes.
  • sequence/: Diagrams for proximity-based interactions (e.g., NFC/BLE) and API flows.

general/

Contains common assets, shared diagrams, and reusable implementation examples.

• examples/:
  • attestation/: Example attestations in SD-JWT and W3C VC formats (e.g., IBAN attestations).
  • metadata/: Metadata examples for Issuers and Verifiers. These include configurations for IBAN and SUA, with support for various transaction data types (PSD2, Berlin Group, etc.).
• sequence/: General presentation and DC API sequence diagrams.

Key Technologies & Standards & abbrevations

• OpenID4VCI / OpenID4VP: Protocols used for issuance and presentation.
• SD-JWT (Selective Disclosure JWT): see SD-JWT specification
• W3C Verifiable Credentials: W3C data model for credentials.
• SUA (String User Authentication): see SUA specification

---

This repository is part of the WE BUILD consortium's effort to pilot EUDIW in the European banking landscape.