SSH Public Key Exchange
=======================

.. toctree::
   :maxdepth: 1
   :caption: Contents:

.. role:: underline
    :class: underline
    

**To access the login node of Discoverer HPC, the users have to use OpenSSH public key-based authentication (no password-based authentication is available).**

SSH key exchange is required by the :doc:`onboarding`. During that process, the users need to send a copy of their public OpenSSH keys to the Discoverer HPC onboarding team, upon e-mail request.

.. note:: If you do not have any OpenSSH key pair in use, a new key pair can be generated by following the prescriptions in :doc:`ssh_key_generation`.

Linux/macOS
-----------

ECDSA
.....

If your private OpenSSH key is stored in the file:

.. code:: console

  ~/.ssh/id_ecdsa

the corresponding public key should be available in:

.. code:: console

  ~/.ssh/id_ecdsa.pub

.. note:: You need to send the content of ``~/.ssh/id_ecdsa.pub`` during the onboarding process, upon request.

If there is ``~/.ssh/id_ecdsa`` presented but no ``~/.ssh/id_ecdsa.pub`` available, you can generate the public key and store it into ``~/.ssh/id_ecdsa.pub`` by executing:

.. code:: console

 ssh-keygen -y -f ~/.ssh/id_ecdsa > ~/.ssh/id_ecdsa.pub

RSA
...

If your private OpenSSH key is stored in the file:

.. code:: console

  ~/.ssh/id_rsa

the corresponding public key should be available in:

.. code:: console

  ~/.ssh/id_rsa.pub

.. note:: You need to send the content of ``~/.ssh/id_rsa.pub`` during the onboarding process, upon request.

If there is ``~/.ssh/id_rsa`` presented but no ``~/.ssh/id_rsa.pub`` available, you can generate the public key and store it into ``~/.ssh/id_rsa.pub`` by executing:

.. code:: console

 ssh-keygen -y -f ~/.ssh/id_rsa > ~/.ssh/id_rsa.pub

Windows
-------

PuTTY
.....

You can display and then copy the public OpenSSH key by following first part of the procedure "Convert public key" in :doc:`ssh_convert_putty_key_into_openssh_key`, see also the image below as a hint:

.. image:: _images/puttygen_11.png

Cygwin
......

See `Linux/macOS`_.

Getting help
............

See :doc:`help`