# Authenticate

## Overview

The `authenticate` method executes 3D Secure authentication.

## Request Fields

| Field             | Type          | Required | Description        |
| ----------------- | ------------- | -------- | ------------------ |
| `merchantOrderId` | String        | Yes      | Order reference    |
| `amount`          | Money         | Yes      | Transaction amount |
| `paymentMethod`   | PaymentMethod | Yes      | Card details       |

## Response Fields

| Field                | Type   | Description           |
| -------------------- | ------ | --------------------- |
| `status`             | String | AUTHENTICATED, FAILED |
| `authenticationData` | Map    | 3DS results           |

## Example

```java
Map<String, Object> request = new HashMap<>();
request.put("merchantOrderId", "order_001");
request.put("amount", Map.of("minorAmount", 10000, "currency", "USD"));

Map<String, Object> response = authClient.authenticate(request);
```