.. _justus_2:

JUSTUS 2
---------------------

`JUSTUS 2 <https://wiki.bwhpc.de/e/JUSTUS2>`_ is the German nation-wide HPC system for computational chemistry research. If you are based at a research institution in Germany, you probably use Justus 2 for computational chemistry access.

Access to JUSTUS 2 is protected by two-factor authentication, and most logins require both a standard fixed password (called a service password in JUSTUS 2 terminology) and a time-based one-time password (OTP).
Both of these authentication schemes are supported by Digichem.

For general instructions on getting started with JUSTUS 2, please see `<https://wiki.bwhpc.de/e/JUSTUS2/Getting_Started>`_.

Digichem Setup
_______________

To connect to a JUSTUS 2 account using Digichem, follow these steps.

#. Follow the first steps of the :ref:`getting started guide <get_started_connect>` as normal.
#. When you are asked 'How do you normally login?', you should *tick* both the **I use a password** option and the **I use a one-time password** option. Leave the **I use a key file** option *unticked*:
    
   .. image:: /_static/installation/justus/password.png

#. Enter your *service password* in the password field:

   .. image:: /_static/installation/justus/service_pass.png

#. When you click **Next**, you will then be prompted for your OTP:
   
   .. image:: /_static/installation/justus/otp.png

   Retrieve your current time-based one-time password from your smartphone or other device, and enter it into the prompt.

#. That's it! Digichem will then log you in, and you can continue with the remainder of the :ref:`getting started guide <get_started_license>`.


.. hint::
   Remember that one-time passwords on JUSTUS 2 don't last long, and you'll need to generate a new OTP each time you login to JUSTUS 2.