.. yk5-apps-index.rst

.. _yk5-apps-label:

==================================
Protocols and Applications
==================================

The YubiKey 5 Series provides applications for FIDO2, OATH, OpenPGP, OTP, Smart Card (PIV), and U2F. The applications are all separate from each other, with separate storage for keys and credentials.

.. toctree::
   :maxdepth: 1

   yk5-apps-fido
   yk5-apps-piv
   yk5-apps-oath
   yk5-apps-openpgp
   yk5-apps-otp
   yk5-apps-yubihsm-auth


For information on managing all these applications, see :ref:`yk5-tools-label`.

Note that the OTP and OATH categories overlap. Technically, there are three true OTPs:

* Yubico OTP (defined by Yubico)
* OATH-HOTP (standard `RFC4226 <https://datatracker.ietf.org/doc/html/rfc4226>`_)
   
   * We support the **Yubico OTP and OATH-HOTP directly on the touch-triggered OTP function** on the YubiKey.
   
* OATH-TOTP (standard `RFC6238 <https://datatracker.ietf.org/doc/html/rfc6238/>`_)

   * We support **OATH-HOTP and OATH-TOTP directly on the OATH function** on the YubiKey (usually called OATH and used with `Yubico Authenticator <https://www.yubico.com/products/yubico-authenticator/>`_).
   * We support a static password and Challenge-Response with `Touch-triggered OTP <https://developers.yubico.com/Developer_Program/Guides/Touch_triggered_OTP.html>`_. Challenge-Response can also be used with software (such as Yubico Authenticator) to act as a single OATH-TOTP credential.

All three of these OTPs are described in more detail below; see :ref:`oath-label` and :ref:`otp-label`.

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