I'm using PuTTY(MobaXterm), What do we need to register at SSH public key in TSUBAME portal?

Warning: If your SSH private key is leaked, your account will be misused by the third-party. Please secure your private key with setting the passphrase.

This article describes how to create SSH keypair to be used TSUBAME3 using PuTTYgen, which will be installed with PuTTY.
MobaKeyGen from MobaXterm has the same functionarity and UI.

You will get a dialog similar to this by executing PuTTYgen:
PuTTYgen screen

  1. Press "Generate" to create SSH key-pair
    You can adjust key-pair configurations using "Parameters" box, but you don't have to do so in most cases.
  2. Press "Save private key" to save a private key file of generated key-pair for future login.
    After registering public key to TSUBAME3, anyone who can read this private-key file can log in to TSUBAME3 with your account. Please keep this file safe, DO NOT carry with USB stick, or send via e-mail etc.
    You can force to enter passphrase to use this key file, by inputting them in "Key passphrase" and "Confirm passphrase" boxes before saving.
  3. Copy all texts in "Public key for pasting..." box, paste it into "Enter SSH public key code" in "Register SSH public key" menu in TSUBAME portal, and then submit this.

When you want to login into TSUBAME, open the file saved in step 2. with Pageant (.ppk files are associated with Pageant if you install PuTTY using installer with default options) in advance, or specify the file in "Private key file for authentication" box under "Connection"-"SSH"-"Auth" menu in PuTTY connection setting dialog.