# Transaction refusal

If the user doesn't approve the transaction request, the **PKSA** will send a refusal message to the **HAS**. The **HAS** will then forward the following message to the **APP**:

### sign\_nack

```
{
    cmd: "sign_nack",
    uuid: string,
    data: string
}
```

{% tabs %}
{% tab title="Properties" %}

* **`uuid`**: the transaction request identifier
* **`data`**: the `uuid` encrypted with `auth_key` and converted to Base64
  {% endtab %}
  {% endtabs %}