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Before You Begin

Before you begin​

Secure identity management is critical for building trustworthy digital applications. Traditional identity systems rely heavily on centralized databases, usernames, and passwords—making them vulnerable to breaches and phishing.

To address these limitations, the OpenWallet Foundation Labs created the Identity Credential project. It enables decentralized identity issuance and verification, supporting standards like OpenID for Verifiable Credential Issuance (OpenID4VCI) and OpenID for Verifiable Presentations (OpenID4VP).

This project provides:

  • A Kotlin/Android library for mobile wallets to issue and present credentials.

  • A server library for issuing credentials.

In this codelab, you’ll build a minimal end-to-end Verifiable Credential flow using Identity Credential components. You’ll create a Utopia app that first issues a credential from the server, then securely stores it on the mobile device, and finally shares it with a verifier app via QR code or NFC for verification.

Prerequisites​

  • Experience building Android apps in Android Studio

  • Familiarity with authentication flows (OAuth2, OpenID Connect)

  • Basic understanding of Decentralized Identifiers (DIDs) and Verifiable Credentials (VCs)

What you’ll learn​

  • How to integrate the multipaz library in an kmp project

  • How to perform a Credential Offer and retrieve metadata

  • How to request and store a Verifiable Credential on-device

  • How to present a credential to a verifier (using OpenID4VP)

What you’ll need​

  • An Android device or emulator (API level 26 or higher)

  • Android Studio Hedgehog (2023.1.1)+

  • Kotlin 1.8.10+

  • XCode for Mac

  • Internet access for network calls

  • Setup Xcode(for mac only)

    • Open Xcode
    • Open (/Project/iosApp/iosApp.xcodeproj)
    • Select iosApp on left Panel
    • Click Signing&Capabilities tab
    • Under Team, select your Apple developer team

Libraries in this Codelab​

ModulePurpose
identity-credentialCore SDK for issuing, storing, and presenting credentials
multipaz-doctypesSample document types (CBOR serializable)
multipaz-modelsCore data models (credential metadata, request, etc.)
multipaz-composeUI helpers for rendering credential-related composables (optional)

Project structure​

You’ll work with these components:

  1. Mobile Wallet App (Android/iOS)
    Retrieves credential offer, obtains credential, and stores locally and verification

  2. Verifier App(Verification)
    Leverage the existing Verifier App to perform credential verification.

  3. Issuer Server
    Issues credentials using OpenID4VCI.