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

Sample PIN display screen in the Issuer Application

Flow

High-level flow to display a PIN

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.

Sequence diagram for PIN display

CardPINUI contains PINDisplayTextView (Android) and D1PINDisplayTextField (iOS), which inherit from the native TextView and 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	Issuer <- Thales D1	Retrieve the PIN from Issuer backend in order to display it on the mobile.

SDK

Androïd

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
    }
});

iOS

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