OpenID4VP

OpenID4VP - Online Sharing

This library enables consumer applications (mobile wallet) to share users Verifiable Credentials with Verifiers who request them online. It adheres to the OpenID4VP specification draft version 23, which outlines the standards for requesting and presenting Verifiable Credentials.

Library Functionalities: Processing the Request from Decoding to Verifier Response

1. Receives the Verifier's Authorization Request sent by the consumer application (mobile wallet).

2. Validates the received Authorization Request to check if the required details are present or not, and then returns the Authorization Request to the consumer application once all the validations are successful.

3. Receives the list of Verifiable Credentials from the consumer application which are selected by the consumer application end-user based on the credentials requested as part of Verifier Authorization request.

4. Constructs the vp_token without proof section and sends it back to the consumer application for generating Json Web Signature (JWS).

5. Receives the generated signature along with the other details and generates vp_token with proof section & presentation_submission.

6. Sends a POST request with generated vp_token and presentation_submission to the received Verifier's response_uri endpoint.

7. Below sections details on the steps for integrating the Kotlin and Swift packages into the app. Below sections details on the steps for integrating the Kotlin and Swift packages into the app.

Supported features

Feature	Supported values
Device flow	Cross device flow, Same device flow (only direct_post and direct_post.jwt supported)
Client id scheme	pre-registered, redirect_uri, did
Signed authorization request verification algorithms	Ed25519
Obtaining authorization request	- By value : both signed (via request param) and unsigned (via URL encoded parameters) - By reference ( via request_uri method) Note: The use of signed or unsigned requests, is determined by the client_id_scheme associated with the client.
Obtaining presentation definition in authorization request	By value, By reference (via presentation_definition_uri)
Authorization Response content encryption algorithms	A256GCM
Authorization Response key encryption algorithms	ECDH-ES
Credential formats	ldp_vc, mso_mdoc, dc+sd-jwt, vc+sd-jwt
Authorization Response mode	direct_post, direct_post.jwt (with encrypted & unsigned responses) and iar-post (unencrypted response), iar-post.jwt (Encrypted and unsigned response)
Authorization Response type	vp_token

Android: Kotlin package for OpenID4VP:

Repository

• inji-openid4vp kotlin repo - here

Installation

Snapshot builds are available - aar and jar

Note: implementation "io.inji:inji-openID4VP:0.7.0"

iOS: Swift package for OpenID4VP:

Repository

• inji-openid4vp-ios-swift swift repo -> here

Installation

1. Clone the repo.

2. In your swift application go to file > add package dependency > add the https://github.com/inji/inji-openid4vp-ios-swift in git search bar > add package.

3. Import the library and use.

APIs

The OpenID4VP library provides the following APIs for implementing the OpenID4VP flow:

API Method	Use Case
authenticateVerifier	Validate and decode the verifier's authorization request
constructUnsignedVPToken	Create unsigned VP tokens (V1 API) from verifiable credentials for signing by the wallet
constructUnsignedVPTokenV2	Create flattened list of unsigned VP tokens (V2 API) with signing metadata for simplified workflow
constructVPResponse	Construct the VP response (V1 API) with signed tokens ready to be sent to the verifier
constructVPResponseV2	Construct the VP response (V2 API) from simplified signing results
sendVPResponseToVerifier	Construct VP response and send it to the verifier via HTTP POST
constructErrorInfo	Construct an authorization error response as per OpenID4VP specification
sendErrorInfoToVerifier	Construct and send error response to the verifier via HTTP POST

For detailed API reference including parameters, response structures, examples, and exceptions, refer to the Kotlin API Reference or Swift API Reference accordingly.

OpenID4VP library and Inji Wallet integration:

The below diagram shows the interactions between Inji Wallet, Verifier and OpenID4VP library.

Note: Currently, the vp_token uses the Ed25519Signature2020 type for digital signatures.