Setting up SSH access to ui.sci.unican.es

This guide explains how to generate a secure SSH key pair on your local computer and register it for access to ui.sci.unican.es.

1. Generate an SSH Key Pair

Open a terminal on your local machine and run:

cd $HOME
ssh-keygen -t ed25519 -f .ssh/id_ed25519-ui

When prompted:

Enter passphrase (empty for no passphrase): ********
  • Enter a strong passphrase (at least 8 characters, including letters, numbers, and symbols).
  • This passphrase protects your private key and will be required each time you use it.

You will see output similar to:

Generating public/private ed25519 key pair.
Your identification has been saved in /nfs/home/<group>/<username>/.ssh/id_ed25519-ui
Your public key has been saved in /nfs/home/<group>/<username>/.ssh/id_ed25519-ui.pub

2. Copy Your Public Key to ui.sci.unican.es

Now send your public key to your SCI account using the following command:

ssh-copy-id -i .ssh/id_ed25519-ui.pub <your_username>@ui.sci.unican.es

Replace your_username> with your actual SCI account username.

You will be asked for your SCI account password (not the SSH key passphrase).
Once this step is complete, your key will be installed on the remote system.

3. Connect Using Your SSH Key

To test the connection, use:

ssh -i .ssh/id_ed25519-ui <your_username>@ui.sci.unican.es

You should now be prompted for your SSH key passphrase, like this:

Enter passphrase for key '.ssh/id_ed25519-ui':

Enter the passphrase you set earlier.
If everything is correct, you will be logged into ui.sci.unican.es.

Summary

Step Command Description
1 ssh-keygen -t ed25519 -f .ssh/id_ed25519-ui Create a new key pair
2 ssh-copy-id -i .ssh/id_ed25519-ui.pub <your_username>@ui.sci.unican.es Add the key to the SCI server
3 ssh -i .ssh/id_ed25519-ui <your_username>@ui.sci.unican.es Connect using your SSH key

Tips

  • Your keys are stored in ~/.ssh/:
  • Private key → id_ed25519-ui
  • Public key → id_ed25519-ui.pub
  • Never share your private key (id_ed25519-ui).
  • Use a password manager to store your SSH passphrase safely.
  • You can use ssh-add to cache your passphrase temporarily: bash ssh-add ~/.ssh/id_ed25519-ui