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Create an SSH key pair

Phoebe and Koios accept only SSH key logins. A key pair has two parts: a private key that stays on your computer, and a public key that you send to the administrators.

If you do not have an SSH key pair yet, open a terminal and run:

ssh-keygen -t ed25519

ssh-keygen then asks two questions:

  1. Enter file in which to save the key: press Enter to accept the default location (~/.ssh/id_ed25519).
  2. Enter passphrase: type a strong passphrase and repeat it. If your disk is encrypted, you may leave it empty and just press Enter twice.
Example output 
Generating public/private ed25519 key pair.
Enter file in which to save the key (/home/testuser/.ssh/id_ed25519):
Created directory '/home/testuser/.ssh'.
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /home/testuser/.ssh/id_ed25519
Your public key has been saved in /home/testuser/.ssh/id_ed25519.pub
The key fingerprint is:
SHA256:SLKcljiOmsdTubEGeG+6QP+nDs0NoLciBA71guz8BXQ testuser@hostname
The key's randomart image is:
+--[ED25519 256]--+
|  .. E           |
|.o...            |
|+..oo .          |
|* .+o* .         |
| Oo.*+. S        |
|+o*oO o          |
|++.O * .         |
|oo= O  .         |
|o.o*.+o          |
+----[SHA256]-----+

Print your public key and send it to the CEICO HPC administrator:

cat ~/.ssh/id_ed25519.pub

Warning

Never share the private key ~/.ssh/id_ed25519 (the file without .pub).

Install MobaXterm, a terminal for Windows with a built-in SSH client, then:

  1. Click Tools → MobaKeyGen.
  2. Choose the key type EdDSA (Ed25519).
  3. Click Generate and move your mouse over the blank area to generate some randomness.
  4. Type a strong passphrase into Key passphrase and repeat it in Confirm passphrase.
  5. Click Save private key and save it somewhere safe (e.g. your home directory). The file has the extension .ppk.
  6. Copy the Public key for pasting into OpenSSH server field and send it to the CEICO HPC administrator (e.g. by e-mail or Slack).

MobaXterm SSH key generator with an Ed25519 key

Warning

Never share the private key file (.ppk).

Next: request an account with your public key.