Digital Product Passport (DPP) Demo with DIDs & Verifiable Credentials

Overview

This project was developed as an experimental implementation to deepen understanding of how Digital Product Passports (DPPs) can be modeled using Decentralized Identifiers (DIDs) and Verifiable Credentials (VCs).

Note: This project is for demonstration and learning purposes only. It is not suitable for production or security-critical applications.

Key Learning Goals

1. Exploring DID Design and Control Models

   • Understand the implications of different DID methods (did:web, did:key) in practical DPP scenarios.
   • Evaluate how DID Documents serve as a persistent, verifiable reference for product identity and metadata.

2. Experimenting with Verifiable Credentials (VCs)

   • Implement credential issuance and discovery flows.
   • Explore how product information (materials, provenance, compliance) can be expressed as structured and verifiable data.
   • Test how credentials can be “anchored” to DIDs to support traceability and authenticity.

3. Understanding the User Journey in DPP Systems

   • Simulate interactions between actors (Business, Client) to identify usability and data flow challenges.
   • Reflect on how user agents (wallets) can provide intuitive interfaces for credential exchange and verification.

Research and Inspiration

This learning exploration builds upon insights and design principles from the following key resources:

• Digital Product Passport Management with Decentralised Identifiers and Verifiable Credentials
• United Nations Transparency Protocol: DPP
• Implementing Digital Product Passports using decentralized identity standards

Getting Started

1. Installation

git clone https://github.com/Jorge-Lopes/dpp-did.git
cd dpp-did
make install

2. Run Wallet Unit Tests

cd wallet
npm test

Run the Demo

Open three terminal windows for the following processes:

Terminal 1 – Docker manager

Start all containners:

make system-up

Terminal 2 – Business Wallet

Set up the Wallet and generate Business DID:

make business-wallet-init

Create new Product and generate Product DID:

make business-wallet-product

Generate Product Verifiable Credential:

DID will be set as did:web:business_server%3A7003:products:0

make business-wallet-credential PRODUCT_DID=<DID>

Terminal 3 – Client Wallet

Set up the Wallet and generate Client DID:

make client-wallet-init

Get Product DID Document from Product DID:

DID will be set as did:web:business_server%3A7003:products:0

make client-wallet-get-did DID=<DID>

Get Product Verifiable Credential from service endpoint

PATH will be set as /products/0/credentials/materials.json

make client-wallet-get-credential PATH=<PATH>

Workflow: The “Happy Path”

Actors

• Business – creates and issues product DIDs and VCs.
• Client – verifies product information and assumes ownership.

Components

• Business Wallet
• Business DID (did:web)
• Business Local Server (web domain)
• Client Wallet
• Client DID (did:key)
• Product DID (did:web)
• Product Verifiable Credential(s)

Sequence Diagram

sequenceDiagram
   participant MW as Business Wallet
   participant MS as Business Server
   participant CW as Client Wallet

   %% --- Product Creation ---
   MW->>MW: Generate Product DID (Business DID as controller)
   MW->>MS: Store it on Business Server (same as DID domain)
   MW->>MW: Issue VC with product data (Product DID as subject)
   MW->>MW: Anchor VC to DID document
   MW->>MS: Store it on Business Server

   %% --- Product Discovery ---
   Note over CW: Client scans product data carrier
   CW->>MS: Fetch Product DID Document
   MS-->>CW: Return DID Document
    Note over CW: Obtain VC URL from Product DID Document service endpoint
   CW->>MS: Fetch product VCs
   MS-->>CW: Return Product VC
   CW->>CW: Verify VC integrity using Product DID Document service hash

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Improvements to be made

• Improve file system management between the business wallet and the business server
• Implement wallet to wallet messaging protocol similar to DIDComm
• Improve testing coverage