SSH Keys

A key pair may be used in place of a password for SSH or SFTP authentication. This is a convenient and secure way to authenticate.

Mac/Linux

Use the built-in ssh-keygen tool to generate your key pair.

ssh-keygen -t rsa -b 4096

You will be prompted save the key files. Press Enter to accept the default value.

Generating public/private rsa key pair.
Enter file in which to save the key (/Users/username/.ssh/id_rsa):

You will be prompted to enter a passphrase to save. Use a strong password with complexity and length.

Enter passphrase (empty for no passphrase):
Enter same passphrase again:

Add the new private key to your computer's list of keys. Your private key is the file without the .pub extension. You will be prompted for your passphrase.

ssh-add id_rsa

To complete this setup for cluster login, copy your public key to the cluster login node.

cat ~/.ssh/id_rsa.pub | ssh NetID@login-hpc.rcc.mcw.edu 'cat >> .ssh/authorized_keys

Test your setup by logging in to the cluster. A successful login should not prompt you for a password.

Windows

MobaXterm CLI

MobaXterm supports a similar functionality for Windows users. To generate a key pair, open MobaXterm and select Start local terminal.

Use the built-in ssh-keygen tool to generate your key pair.

ssh-keygen -t rsa -b 4096

You will be prompted save the key files. Press Enter to accept the default value.

Generating public/private rsa key pair.
Enter file in which to save the key (/Users/username/.ssh/id_rsa):

You will be prompted to enter a passphrase to save. Use a strong password with complexity and length.

Enter passphrase (empty for no passphrase):
Enter same passphrase again:

Copy your public key to the cluster login node.

cat ~/.ssh/id_rsa.pub | ssh NetID@login-hpc.rcc.mcw.edu 'cat >> .ssh/authorized_keys

To complete the setup, first logout of all shells and close MobaXterm. Open a new MobaXterm window and select Session. In the Session menu, select SSH. Enter the remote host, login-hpc.rcc.mcw.edu. Select Specify username and enter your MCW username. Select Use private key and enter the private key you generated (should be automatic).

Select the icon to the right of the username field to open the Password settings window. Finally, select Save SSH keys passphrases as well, and close this window.

To test your setup, login by selecting Ok. Your first successful login should prompt you for your private key passphrase, but not your password. Subsequent logins should not prompt for either password.

MobaXterm GUI

If you do not want to use command-line, try the MobaKeyGen tool in MobaXterm.

Adjust the default settings so that key type is RSA, and key length is 4096. Select Generate, and move your mouse over the open space.

You should see key information. Enter an optional comment and a secure passphrase. Use a strong password with complexity and length. Lastly, save your public and private keys.

Security

Private SSH Key

Treat your private key like a password. Do not share it with anyone. We will never ask you for your private key or your password.