> ## Documentation Index
> Fetch the complete documentation index at: https://docs.rocka.live/llms.txt
> Use this file to discover all available pages before exploring further.

# Security checks

If you're using `returnUrl` and/or `webhookUrl` to handle payment or payout results, add quick security checks to prevent bank fraud.

## Anti-fraud security checks

1. **Verify the payment signature:**

Use this formula to verify the payment signature:

```text theme={null}
signature = sha256(paymentId + status + signatureKey)
```

The `signatureKey`is unique to your account and ensures the payment result data is authentic.

2. **Prevent duplicate signatures:**

This makes sure the payment result isn't duplicated. Fraudsters can't create a valid signature without your `signatureKey`, but they can intercept a legitimate result and try to resend it. To prevent this, implement duplicate detection:

* Compare the `paymentId` of the current order with the one in the payment result.
* Store every `paymentId` that has been processed and reject any repeated submissions with the same ID.