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

# Introduction to Hanko Authenticator

> Out-of-band and on-device multi-factor authentication with FIDO UAF and the Hanko Authenticator app.

The **Hanko Authenticator** is Hanko's implementation of the [FIDO Universal Authentication Framework (FIDO UAF)](/hanko-authenticator/what-is-fido-uaf) protocol. It lets you add strong, passwordless multi-factor authentication and transaction confirmation to your application using either:

* a white-label **Hanko Authenticator mobile app** that authenticates out-of-band, or
* the **Hanko FIDO UAF Client SDK**, which embeds on-device FIDO UAF authentication directly into your own native Android or iOS app.

Both approaches are built on top of Hanko's certified FIDO server and the same underlying Hanko API.

## Use cases

### Hanko Authenticator & FIDO UAF

FIDO UAF offers a passwordless experience, much like passkeys, but embedded in an app on your user's mobile device. The Hanko Authenticator offers strong two-factor authentication with a customizable white-label design using out-of-band communication.

"Out-of-band" (OOB) communication means that authentication happens over a communication channel separate from the primary one: a user initiates authentication on their desktop and uses their mobile phone to authenticate via a biometric gesture or PIN, in response to a QR code or push notification transmitted via the out-of-band channel.

<Frame>
  <img src="https://mintcdn.com/hanko/DAs0LNceUiIaZd6m/images/hanko-authenticator/usecases-uaf.svg?fit=max&auto=format&n=DAs0LNceUiIaZd6m&q=85&s=ed45115d90c0fe460995744759039307" alt="Hanko Authenticator out-of-band use case" width="769" height="316" data-path="images/hanko-authenticator/usecases-uaf.svg" />
</Frame>

Using OOB communication does not require users to have a desktop device with built-in biometric capabilities or any type of hardware-based key store (e.g. a TPM chip) — it works with any desktop device that has a browser.

[Get started with the Hanko Authenticator app](/hanko-authenticator/quickstart/authenticator-app)

### On-device authentication with the FIDO UAF Client

You can integrate FIDO-based strong multi-factor authentication directly into your existing mobile app using the Hanko FIDO UAF Client, enabling on-device authentication on Android and iOS.

Unlike the Hanko Authenticator, this scenario does not involve out-of-band communication. Instead of initiating communication on a desktop through a browser and confirming it in response to a notification on a mobile device, all communication originates from the mobile device and runs through your app's backend, which passes information to the Hanko API.

<Frame>
  <img src="https://mintcdn.com/hanko/DAs0LNceUiIaZd6m/images/hanko-authenticator/usecases-uaf-on-device.svg?fit=max&auto=format&n=DAs0LNceUiIaZd6m&q=85&s=1062fd1a6159f64ee79e87a044ed2384" alt="Hanko FIDO UAF Client on-device use case" width="851" height="331" data-path="images/hanko-authenticator/usecases-uaf-on-device.svg" />
</Frame>

[Get started with the Hanko FIDO UAF Client for Android or iOS](/hanko-authenticator/quickstart/uaf-client)

## Next steps

<CardGroup cols={2}>
  <Card title="What is FIDO UAF?" href="/hanko-authenticator/what-is-fido-uaf">
    Learn the background and core concepts behind the FIDO UAF protocol.
  </Card>

  <Card title="Core components" href="/hanko-authenticator/core-components">
    Understand the pieces that make up the Hanko Authenticator service.
  </Card>

  <Card title="Quickstart: Hanko Authenticator app" href="/hanko-authenticator/quickstart/authenticator-app">
    Register and authenticate devices with the out-of-band mobile app.
  </Card>

  <Card title="Quickstart: FIDO UAF Client SDK" href="/hanko-authenticator/quickstart/uaf-client">
    Add on-device FIDO UAF authentication to your native Android or iOS app.
  </Card>
</CardGroup>