> For the complete documentation index, see [llms.txt](https://docs.inji.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.inji.io/inji-wallet/inji-mobile/technical-overview/integration-guide/building-verifiable-credentials-wallet-with-inji-libraries/openid4vp.md).
# OpenID4VP Library
## Verifiable Presentation - Online Sharing
This library is for **wallet-side** processing of [OpenID for Verifiable Presentations](https://openid.net/specs/openid-4-verifiable-presentations-1_0.html) (OpenID4VP). This library validates incoming authorization requests, helps build Verifiable Presentations (with signing delegated to your app), and sends responses to the verifier.
**Key Responsibilities:**
* **OpenID4VP Library**
* Handles OpenID4VP protocol workflows and compliance
* Simplifies Verifiable Presentation creation and response exchange
* Reduces development complexity and integration time
* **Library Consumer App**
* Owns user consent and credential selection
* Performs secure cryptographic signing
Build OpenID4VP capabilities faster with a library designed to remove protocol complexity, reduce implementation risk, and accelerate your journey toward interoperable digital credentials.
## Supported features
### Feature Matrix by Specification Version
**Legend:** ✅ = Supported | ❌ = Not Implemented | N/A = Not Applicable
| Feature | Draft 23 | Version 1.0 | Notes |
| --------------------------------------------- | :-------: | :---------: | ------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| **Device Flow** | | | |
| Cross device flow | ✅ | ✅ | Wallet scans QR code and passes data to this library |
| Same device flow | ✅ | ✅ | Wallet receives VP request via deeplink |
| **Client ID Prefix** | | | Equivalent to Client ID Scheme in draft 23 |
| pre-registered | ✅ | ✅ | Validated via `WalletConfig.trustedVerifiers` |
| redirect\_uri | ✅ | ✅ | |
| decentralized\_identifier | ✅ (`did`) | ✅ | |
| **Authorization Request Delivery** | | | Per [RFC 9101](https://www.rfc-editor.org/info/rfc9101/#name-authorization-request) |
| By value (signed request) | ✅ | ✅ | |
| By value (unsigned request) | ✅ | ✅ | Via URL-encoded parameters |
| By reference (request\_uri) | ✅ | ✅ | Fetched via HTTP GET/POST |
| Request signing algorithms | ✅ | ✅ | Ed25519 |
| **Presentation Request** | | | |
| DCQL Query | ❌ | ✅ | |
| Presentation Definition | ✅ | ❌ | By value or via `presentation_definition_uri` |
| Scope parameter | ❌ | ❌ | Not implemented |
| **VP Response Modes** | | | |
| direct\_post | ✅ | ✅ | |
| direct\_post.jwt | ✅ | ✅ | Unsigned and Encrypted response |
| iar-post / iae\_post | ✅ | ✅ | |
| iar-post.jwt / iae\_post.jwt | ✅ | ✅ | Unsigned and Encrypted response |
| **VP Response Type** | | | |
| vp\_token | ✅ | ✅ | |
| vp\_token id\_token | ❌ | ❌ | Not implemented |
| code | ❌ | ❌ | Not implemented |
| **Authorization Response Encryption** | | | For `direct_post.jwt` and `iar-post.jwt` / `iae_post.jwt` modes |
| Encryption algorithm (content) | ✅ | ✅ | A256GCM |
| Key agreement algorithm | ✅ | ✅ | ECDH-ES |
| **VP Token Generation** | | | |
| DCQL Query-based | ❌ | ✅ | |
| Presentation Definition-based | ✅ | ❌ | |
| Error responses | ✅ | ✅ | Any failure during VP request validation / user consent rejection / VP response preparation is prepared as Authorization Error response and sent to Verifier |
| **Supported Verifiable Presentation Formats** | | | |
| ldp\_vp | ✅ | ✅ | |
| mso\_mdoc | ✅ | ✅ | |
| vc+sd-jwt / dc+sd-jwt | ✅ | ✅ | |
## Platform & Library Support
This library is available in Kotlin and Swift, supporting Android, JVM and iOS platforms.
* **Kotlin**: [Android (AAR) & JVM (JAR)](https://github.com/inji/inji-openid4vp/tree/master/kotlin)
* **Swift**: [iOS](https://github.com/inji/inji-openid4vp-ios-swift)
### Core Methods
The library provides the following methods organized into different workflow patterns:
#### Primary Flow Methods
| Method | Purpose |
| -------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------ |
| **`authenticateVerifier()`** | Validates incoming authorization requests from verifiers. Resolves request objects, verifies signatures, and returns a structured request. |
| **`getMatchingCredentials()`** | *(DCQL Helper)* Evaluates DCQL queries against your wallet's credentials to determine which satisfy the verifier's requirements. |
| **`constructUnsignedVPToken()`** | Prepares VP tokens based on selected credentials. Returns unsigned data that your wallet must sign. |
#### Response Submission: Two Patterns Available
**Option 1: Construct & Send (Recommended)** — SDK handles VP Response submission
| Method | Purpose |
| -------------------------------- | -------------------------------------------------------------------------------------------------------- |
| **`sendVPResponseToVerifier()`** | Assembles signed VP tokens into an OpenID4VP response **and submits it** to the verifier. |
| **`sendErrorInfoToVerifier()`** | Constructs and sends error/rejection responses to the verifier (e.g., user denial, validation failures). |
**Option 2: Construct Only (Advanced)** : You handle VP Response submission yourself
| Method | Purpose |
| --------------------------- | ------------------------------------------------------------------------------------ |
| **`constructVPResponse()`** | Constructs the VP response **without sending**. You handle VP Response submission. |
| **`constructErrorInfo()`** | Constructs an error response **without sending**. You handle VP Response submission. |
> **For detailed API reference including parameters, response structures, examples, and exceptions, refer to the** [**Kotlin API Reference**](https://github.com/inji/inji-openid4vp/tree/master/docs/integration-guide.md) **or** [**Swift API Reference**](https://github.com/inji/inji-openid4vp-ios-swift/docs/integration-guide.md) **accordingly.**
#### OpenID4VP library and Wallet integration:
The below diagram shows the interactions between Wallet, Verifier and OpenID4VP library.
```mermaid
sequenceDiagram
participant Verifier as 🔍 Verifier
participant Wallet as 📱 Wallet
participant Library as 📚 OpenID4VP Library
Note over Verifier: Generate QR Code with
Authorization Request
Wallet -->> Verifier: Scan QR Code
Wallet -->> Library: Forward Authorization Request
activate Library
Note over Library: Validate Request against:
1. Client ID
2. Response URI
3. Trusted Verifiers
Note over Library: Validate Required Fields
and Values
deactivate Library
Library-->>Wallet: Return Validated Authorization
activate Wallet
Note over Wallet: Display Matching VCs
to User
deactivate Wallet
Wallet-->>Library: Send Selected VCs
with User Consent
Library-->>Library: Construct VP Token
Library-->>Wallet: Return the unsigned VP Token
activate Wallet
Note over Wallet: Sign VP Token
deactivate Wallet
Wallet-->>Library: Send Signed data
activate Library
Note over Library: Create Verifiable Presentation
Note over Library: Populate VP response
deactivate Library
Library-->>Verifier: HTTP POST Request with: VP Response
```
---
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