> For the complete documentation index, see [llms.txt](https://dev-docs.tasknet.co/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://dev-docs.tasknet.co/getting-started/authentication/fingerprints.md).

# Fingerprints

{% hint style="warning" %}
Optimally, store the fingerprintSecret on the user device. It cannot be retrieved once lost.
{% endhint %}

An optional feature that enhances session management. By using a `fingerprintSecret`, you can encrypt session data, ensuring it can only be decrypted with both the `fingerprintSecret` and the `envSecret`. This adds an extra layer of security for persistent sessions.

To authenticate a session fingerprint, you must include `fingerprintSecret`in the request headers.

{% content-ref url="/pages/QyontvOxZpoUS3Avfn4O" %}
[User Fingerprints](/features/user-fingerprints.md)
{% endcontent-ref %}

{% content-ref url="/pages/BofI0KDi793ELF7FrgeO" %}
[Fingerprints](/reference/api-reference/fingerprints.md)
{% endcontent-ref %}

<table><thead><tr><th width="322">Header Key</th><th>Value</th></tr></thead><tbody><tr><td>X-Fingerprint-Secret</td><td><pre><code>fingerprintSecret
</code></pre></td></tr></tbody></table>


---

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