> For the complete documentation index, see [llms.txt](https://docs.payments.thalescloud.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.payments.thalescloud.io/3d-secure/integrate-d1-sdk/get-started/3.-initialization/3ds-initialization.md).

# 3DS initialization

D1 SDK provides the facility to initialize the 3DS features. This must be done each time the application starts.

The issuer application will need to set up:

* UI callbacks for handling the user interactions initiated by 3DS for user verification.
* Push token used by the D1 SDK for [push notification](https://app.gitbook.com/o/fwy1mtbRONGA2YDKDBr0/s/62lLFDcmLCeqqwmy4Fee/integrate-d1-sdk/getting-started/configuration/4.-push-notifications/push-notification-configuration).

### Initialization steps

<figure><img src="/spaces/62lLFDcmLCeqqwmy4Fee/files/FZ39tUrj45jCQLIfqdvS" alt=""><figcaption><p>3DS initialization steps</p></figcaption></figure>

#### Init D1Authn

{% tabs %}
{% tab title="Android" %}
{% code overflow="wrap" lineNumbers="true" %}

```java
AuthnCallback authnCallback = new AuthnCallback() {
        @Override
        public void onTransactionDataConfirmation(@NonNull Map<String, String> map, @NonNull AuthnUserConfirmationCallback authnUserConfirmationCallback) {
            // Compose transaction details message using JSON payload received.
            String message = "";
            android.app.AlertDialog.Builder builder = new android.app.AlertDialog.Builder(activity)
                    .setTitle("Transaction Details")
                    .setMessage(message)
                    .setPositiveButton("OK", (dialog, which) -> {
                        authnUserConfirmationCallback.proceed();
                        dialog.dismiss();
                    }).setNegativeButton("Cancel", (dialog, which) -> {
                        authnUserConfirmationCallback.cancel();
                        dialog.dismiss();
                    });
            android.app.AlertDialog alertDialog = builder.create();
            alertDialog.setCanceledOnTouchOutside(false);
            alertDialog.show();
        }

        @NonNull
        @Override
        public String onBiometricPromptMessage() {
            return <Message to be displayed to the user during biometric prompt>
        }
};

D1Authn d1Authn = d1Task.getD1Authn(activity, authnCallback);
```

{% endcode %}
{% endtab %}

{% tab title="iOS" %}
{% code overflow="wrap" lineNumbers="true" %}

```swift
extension ViewController: AuthnDelegate {
    public func authn(_ authn: D1Authn, shouldConfirmTransactionData transactionData: [String : String], proceedHandler: (@escaping() -> Void), cancelHandler: (@escaping() -> Void)) {

        // Compose transaction details message using JSON payload received.
        var message = ""

        // Display the transaction details message to the end user, with the option to proceed or cancel.
        let alertController = UIAlertController(title: "Transaction Details", message: message, preferredStyle: .alert)
        alertController.addAction(UIAlertAction(title: "Proceed", style: .default, handler: { action in
            proceedHandler()
        }))
        alertController.addAction(UIAlertAction(title: "Cancel", style: .cancel, handler: {action in
            cancelHandler()
        }))
        present(alertController, animated: true)
    }

    public func authnTouchIDOperationPrompt(_ authn: D1Authn) -> String {
        return <Message to be displayed to the user during Touch ID verification>
    }
}

let d1Authn = d1Task.d1Authn(self)
```

{% endcode %}
{% endtab %}
{% endtabs %}


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