> 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/pin-management/implement-pin-management/display-a-pin.md).

# Display a PIN

This section describes how to display the card PIN securely.

D1 currently supports **PIN block ISO 0** returned by the **issuer backend**.

### User Experience

<figure><img src="/files/uixZNJSzKkGZUFDdbNeT" alt=""><figcaption><p>Sample PIN display screen in the Issuer Application</p></figcaption></figure>

### Flow

<figure><img src="/files/bAwvEIQJI0qYkQIbPDUN" alt=""><figcaption><p>High-level flow to display a PIN</p></figcaption></figure>

1. **End user** authenticates in the **issuer application** and requests the PIN.
2. Issuer application calls the D1 SDK PIN display method.
3. D1 SDK calls the **D1 backend** “Get PIN” API.
4. D1 backend requests the PIN block from the **issuer backend** (D1 does not store PINs).
5. D1 backend **transciphers** the PIN block from issuer keys to device keys.
6. SDK displays the PIN in a secure UI for a limited time.

### Sequence Diagram

#### Pre-requisites

* End user, account and card already registered in D1
* SDK is properly initialized
* Issuer App called D1 SDK login API.
* Issuer backend exposes the “Get PIN” endpoint and returns **PIN block ISO 0**.

<figure><img src="/files/WJ1uLRucsBbsJbmJR6nu" alt=""><figcaption><p>Sequence diagram for PIN display</p></figcaption></figure>

`CardPINUI` contains `PINDisplayTextView` (Android) and `D1PINDisplayTextField` (iOS), which inherit from the native [TextView](https://developer.android.com/reference/android/widget/TextView) and [UITextField](https://developer.apple.com/documentation/uikit/uitextfield). Text field configuration (font, size, color) can be done using these native objects properties.

### Security and compliance

* PIN display occur in a secure, tamper‑resistant UI.
* PIN data is not persisted on the device.
* Data exchange is encrypted end‑to‑end.
* Solution is designed to be PCI DSS compliant for PIN handling.

### Required APIs

| API                                                                                                                                                          | Inbound/Outbound    | Description                                                                |
| ------------------------------------------------------------------------------------------------------------------------------------------------------------ | ------------------- | -------------------------------------------------------------------------- |
| [Get PIN](/pin-management/integrate-the-d1-api/d1-api-reference/outbound-api-from-d1/pin-management-api.md#get-cms-api-v1-issuers-issuerid-cards-cardid-pin) | Issuer <- Thales D1 | Retrieve the PIN from Issuer backend in order to display it on the mobile. |

### SDK

{% tabs %}
{% tab title="Androïd" %}

```java
PINDisplayTextView pinDisplayTextView = <Object of type PINDisplayTextView>;
CardPINUI ui = new CardPINUI(pinDisplayTextView);
String cardID = "<Card ID>";

d1Task.displayPhysicalCardPIN(cardID, ui, new D1Task.Callback<Void>() {
    @Override
    public void onSuccess(Void data) {
        // Proceed with subsequent flows, the PIN is now being displayed on the text view provided.
    }
    
    @Override
    public void onError(D1Exception exception) {
        // Refer to D1 SDK Integration – Error Management section
    }
});
```

{% endtab %}

{% tab title="iOS" %}

```swift
let displayTextField = <Object of type D1PINDisplayTextField>
let cardPINUI = CardPINUI(pinTextField: displayTextField)
let cardID = <Card ID>

d1Task.displayPhysicalCardPIN(cardID, cardPINUI: cardPINUI) { error in
    if let error = error {
        // Refer to D1 SDK Integration – Error Management section
    } else {
        // Proceed with subsequent flows, the PIN is now being displayed on the text field provided.
    }
}In
```

{% endtab %}
{% endtabs %}


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