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Generating an SSH Key in Windows

Prerequisite: Installing an SSH Client

Please install an SSH client for Windows first.

Generate the Key

Click on Tools and MobaKeyGen (SSH key generator)

In the section Parameters make sure to set the following properties:

  • Type of key to generate: RSA (this is the SSH-2 protocol)
  • Number of bits in a generated key: 4096

If all is set, hit the Generate button.

During generation, move the mouse cursor around in the blank area.

When finished, make sure to protect your generated key with a passphrase. Save the private and public key. The default name under Linux for the public key is and id_rsa for the private key, but you can name them however you want (the .pub is NOT automatically added). Note that in the whole cluster wiki we will use this file naming convention. Also note that the private key will be stored in Putty format (.ppk, this extension is added automatically).

What is your key's passphrase?

You should set a passphrase when generating your private key. This passphrase is used for encrypting you private key to protect it against the private key file theft/being lost. When using the key for login, you will have to enter it (or the first time you load it into the SSH key agent). Note that when being asked for the passphrase this does not occur on the cluster (and is thus unrelated to it) but on your local computer.

Also see SSH Basics for more information.

The gibberish in the textbox is your public key in the format how it has to be submitted to the MDC and Charite (links for this step below). Thus, copy this text and paste it to the SSH-key-submission-web-service of your institution.

Store the private key additionally in the OpenSSH format. To do so, click Conversions and select Export OpenSSH key. To be consistent, give the file the same name as your .ppk private key file above (just without the .ppk).


To summarize, you should end up with three files:

  1. The public key file, it is not required if you copy and submit the SSH public key as described above and in the links below.
  2. id_rsa.ppk This file is only needed if you plan to use Putty.
  3. id_rsa This is your private key and the one and only most important file to access the cluster. It will be added to the sessions in MobaXterm and WinSSHFS (if required).

Submit Your Key

As a next step you need to submit the SSH key use these links as: