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

# Security & Authentication

To ensure the security and integrity of every transaction, the Spark API requires a two-part authentication process. All requests must identify the sender and include a digital signature so Nayax can verify that no one has altered the request body.

## Authentication Options

Choose the integration path that matches your project status:

<CardGroup cols={3}>
  <Card icon="key" title="Authentication" href="/docs/integrate-pos-device/spark/security-authentication/spark-authentication">
    Sign requests with the current header-based signature method for new integrations.
  </Card>

  <Card icon="clock-rotate-left" title="Legacy Authentication" href="/docs/integrate-pos-device/spark/security-authentication/spark-legacy-authentication">
    Generate an HMAC signature from the request body to maintain existing integrations.
  </Card>

  <Card icon="screwdriver-wrench" title="Interactive Authentication Tool" href="/docs/integrate-pos-device/spark/security-authentication/spark-auth-tool">
    Build and inspect ciphers and signature headers without writing code.
  </Card>
</CardGroup>