Skip to main content

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 KMP library for mobile wallets to issue and present credentials.

  • Server components for issuing and verifying digital 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​

  • Familiarity with Kotlin Multiplatform (KMP) development

  • Experience building user interfaces with Jetpack Compose

  • Experience building Android apps in Android Studio

  • Basic understanding of building iOS apps with Xcode

  • 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 a 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 29 or higher)

  • Android Studio Hedgehog (2023.1.1)+ or Newer Android Studio

  • Kotlin 1.8.10+

  • Xcode and CocoaPods for Mac

  • An Apple Developer team, a unique app bundle ID, and an App Group if you will run the iOS Holder

  • Internet access for network calls

The Get Set Up page walks through the required CocoaPods, local signing, and App Group setup. It uses the generated Xcode workspace, not the .xcodeproj file.

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 for verification

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

  3. Issuer Server
    Issues credentials using OpenID4VCI.