Tap2iD SDK for Windows - API Reference

Overview

The Tap2iD Windows SDK verifies ISO 18013-5 mobile driver's licenses (mDLs) over BLE and NFC. Use Tap2iDSdk: initialize it once with your license key, then call VerifyMdoc for each session.

• Language: C# / .NET 8.0
• Platform: Windows 10 / 11 (x64)
• Transport: BLE, NFC.
• Standard: ISO/IEC 18013-5:2021

Installation

Add the Credence ID Nexus repository to your NuGet sources in Visual Studio, then install Tap2iDSdk. Requires .NET 8.0 and Windows 11+.

NuGet Source URL

https://nexus.credenceid.com/repository/tap2id-sdk-nuget/

Auto-installed dependencies

Initialize SDK

Call InitSdk once at startup, before any mDL verification. Pass your license key in CoreSdkConfig, and attach result callbacks through InitSdkResultListener.

/// Initializes the SDK with the provided configuration.
public void InitSdk(
    CoreSdkConfig        coreSdkConfig,
    InitSdkResultListener sdkInitlistener
);

CoreSdkConfig

InitSdkResultListener delegates

Example

var config   = new CoreSdkConfig { ApiKey = "YOUR_API_KEY_HERE" };
var listener = new InitSdkResultListener
{
    OnInitializationSuccess = result  => Console.WriteLine("SDK ready"),
    OnInitializationFailure = (e, msg) => Console.WriteLine($"Failed: {e}: {msg}")
};
sdk.InitSdk(config, listener);

Verify mDL

Call VerifyMdocAsync with the engagement string from a QR scan, NFC tap, or BLE discovery. Subscribe to DelegateVerifyState for progress updates.

public Task<Tap2iDResult> VerifyMdocAsync(
    MdocConfig          mdocConfig,
    DelegateVerifyState State,
    CancellationToken   cancellationToken = default
);

MdocConfig Properties

VerifyState Lifecycle

Example

var config = new MdocConfig
{
    DeviceEngagementString           = qrCodeData,
    EngagementMode                   = DeviceEngagementMode.QrCode,
    BleConnectionTimeout             = 15,
    BleConsentAndDataTransferTimeout = 45
};
Tap2iDResult result = await sdk.VerifyMdocAsync(config, new DelegateVerifyState
{
    OnVerifyState = state => Console.WriteLine($"→ {state}")
});

VerifiedDocument

Retrieve Data

Iterate through Namespaces and their Items to access attribute values. Binary fields like portrait and signature_usual_mark are returned as byte[].

foreach (var doc  in result.Documents)
foreach (var ns   in doc.Namespaces)
foreach (var item in ns.Items)
{
    if (item.Key == "portrait" && item.Value is byte[] img)
        { /* render as ImageSource */ continue; }

    Console.WriteLine($"{item.Key}: {item.Value}");
}

Security Status

Each VerifiedDocument has an AuthenticationResult with five checks. Review them before trusting the data.

var auth = doc.Authentication;
bool isTrusted    = auth.TrustAttributes.IsIssuerTrusted;
bool deviceSigned = auth.SecurityChecks.IsDeviceSignedValid;
bool issuerSigned = auth.SecurityChecks.IsIssuerSignedValid;
bool digestsValid = auth.SecurityChecks.AreDigestsValid;
var  msoStatus    = auth.MsoValidity.Status; // Valid | NotYetValid | Expired

foreach (var err in auth.ValidationErrors)
    Console.WriteLine($"Error: {err.Message}");

Class Reference

NfcCommunicationException

Thrown when an error occurs during NFC data exchange.

CommunicationBleCentralClientMode

Manages the BLE Central role for reading from a holder device acting as a peripheral.

Error Codes

Returned via Tap2iDResult.ResultError and the OnInitializationFailure callback.

SDK / License

Transaction / Connection

Supported Hardware

BLE Dongles

The BLE transport uses the Bumble library and requires a compatible USB Bluetooth adapter.

NFC Readers

Any PC/SC-compatible USB NFC reader. Most readers work with the standard Windows drivers.

QR / Barcode

Any built-in or USB webcam, or USB barcode scanner operating as a standard HID / keyboard wedge device.