# Post-authenticate

## Overview

The `post_authenticate` method validates 3D Secure authentication results with the issuing bank.

**Business Use Case:** After customer completes a 3DS challenge, validate results before processing payment.

## Purpose

| Scenario        | Action            |
| --------------- | ----------------- |
| After challenge | Validate response |
| Before payment  | Confirm success   |
| Liability shift | Obtain ECI/CAVV   |

## 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                |
| `authentication_data` | dict          | No       | 3DS result data             |

## Response Fields

| Field                      | Type | Description                   |
| -------------------------- | ---- | ----------------------------- |
| `connector_transaction_id` | str  | Connector's authentication ID |
| `status`                   | str  | AUTHENTICATED, FAILED         |
| `authentication_data`      | dict | Validated 3DS data            |
| `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"}
        }
    },
    "authentication_data": {
        "eci": "05",
        "cavv": "AAABBIIFmA=="
    }
}

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

### Response

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

## Next Steps

* [Payment Service](https://docs.hyperswitch.io/integrations/prism/python/payment-service) - Authorize with 3DS data