# Authenticate

## Overview

The `authenticate` method executes the 3D Secure authentication step.

**Business Use Case:** After initiating 3DS with pre\_authenticate, this handles the actual authentication.

## Purpose

| Flow Type    | What Happens                 |
| ------------ | ---------------------------- |
| Frictionless | Completes without action     |
| Challenge    | Presents bank challenge page |

## Request Fields

| Field               | Type          | Required | Description                          |
| ------------------- | ------------- | -------- | ------------------------------------ |
| `merchant_order_id` | str           | Yes      | Your unique order reference          |
| `amount`            | Money         | Yes      | Transaction amount                   |
| `payment_method`    | PaymentMethod | Yes      | Card details                         |
| `return_url`        | str           | No       | URL to redirect after authentication |

## Response Fields

| Field                      | Type | Description                    |
| -------------------------- | ---- | ------------------------------ |
| `connector_transaction_id` | str  | Connector's authentication ID  |
| `status`                   | str  | AUTHENTICATED, FAILED, PENDING |
| `authentication_data`      | dict | 3DS results                    |
| `status_code`              | int  | HTTP status code               |

## Example

### SDK Setup

```python
from hyperswitch_prism import PaymentMethodAuthenticationClient

auth_client = PaymentMethodAuthenticationClient(
    connector='stripe',
    api_key='YOUR_API_KEY',
    environment='SANDBOX'
)
```

### Request

```python
request = {
    "merchant_order_id": "order_001",
    "amount": {
        "minor_amount": 10000,
        "currency": "USD"
    },
    "payment_method": {
        "card": {
            "card_number": {"value": "4242424242424242"},
            "card_exp_month": {"value": "12"},
            "card_exp_year": {"value": "2027"}
        }
    }
}

response = await auth_client.authenticate(request)
```

### Response

```python
{
    "connector_transaction_id": "pi_3Oxxx...",
    "status": "AUTHENTICATED",
    "authentication_data": {
        "eci": "05",
        "cavv": "AAABBIIFmA=="
    },
    "status_code": 200
}
```

## Next Steps

* [post\_authenticate](https://docs.hyperswitch.io/integrations/prism/python/payment-method-authentication-service/post-authenticate) - Validate results