# auth

Call the **auth** API for pre-transaction authentication.

Users can initiate authentication through the UI before starting a transaction. You can either call this API for pre-transaction authentication or skip this API and rely solely on authentication through the **TransactionPermit** SPI.

## Method Signature

```java
void auth(@Nullable AuthInfo method);
```

## Request parameters

| **Item** | **Type** | **Description** | **Required** |
| --- | --- | --- | --- |
| method | [AuthInfo](#cJPAE) | The MPP identity authentication configuration. | Optional |

### AuthInfo

| **Item** | **Type** | **Description** |
| --- | --- | --- |
| isAuth | Boolean | Whether to process authentication: - true: Process authentication - false: Cancel authentication |
| cdCvmInformation | CdCvmInformation | Authentication methods - PATTERN 6 - PASSWORD 7 - FINGERPRINT 8 - FACIAL\_BIOMETRIC 9 - IRIS\_BIOMETRIC 10 - HAND\_GEOMETRY 13 |

## Response parameters

N/A

## Sample

```java
manager = ACTapManager.getInstance(this.getApplication()).isPaymentAvailable();
manager.auth(new AuthInfo(true, CdCvmInformation.FACIAL_BIOMETRIC));
```