Logging in Without a Password (SSH Key Authentication)

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Instead of typing your password each time you connect to the server, you can use an SSH key. It’s more secure and much more convenient.

What is an SSH key?
It's a pair of files: one public (shared with the server) and one private (kept secret on your computer). The server recognizes your public key and lets you in — no password needed.

🔒 Step-by-step: Set Up SSH Key Login

🪟 Windows, Option 🅰️: PowerShell / Windows Terminal

  1. Open PowerShell or Windows Terminal.
  2. Generate your SSH key pair: 
    ssh-keygen
    Press Enter to accept the default location.
  3. Copy the public key to the server: 
    ssh-copy-id yourusername@aurora.fi.muni.cz
    If this doesn't work, use: 
    type $env:USERPROFILE\.ssh\id_*.pub | ssh yourusername@aurora.fi.muni.cz "mkdir -p ~/.ssh && cat >> ~/.ssh/authorized_keys"
  4. Now test it: 
    ssh yourusername@aurora.fi.muni.cz

🪟 Windows, Option 🅱️: PuTTY)

  1. Install PuTTYgen and PuTTY.
  2. Open PuTTYgen and click Generate, then move your mouse until it finishes.
  3. Save your private key (e.g., mykey.ppk).
  4. Copy the public key (the top box) to the server: 
    nano ~/.ssh/authorized_keys
    Paste the key and save with Ctrl+X, Y (as Yes) and Enter.
  5. In PuTTY, go to:
    Connection → SSH → Auth, then browse for your .ppk file.
  6. Connect and you should not be asked for a password.

🍏 macOS

  1. Open the Terminal app.
  2. Run: 
    ssh-keygen
    Press Enter to accept the default path.
  3. Copy your key to the server: 
    ssh-copy-id yourusername@aurora.fi.muni.cz
    Or manually: 
    cat ~/.ssh/id_*.pub | ssh yourusername@aurora.fi.muni.cz "mkdir -p ~/.ssh && cat >> ~/.ssh/authorized_keys"
  4. Test it: 
    ssh yourusername@aurora.fi.muni.cz

🐧 Linux

  1. Open your terminal.
  2. Run: 
    ssh-keygen
    Press Enter to accept the default location.
  3. Send the public key to the server: 
    ssh-copy-id yourusername@aurora.fi.muni.cz
    Or: 
    cat ~/.ssh/id_*.pub | ssh yourusername@aurora.fi.muni.cz "mkdir -p ~/.ssh && cat >> ~/.ssh/authorized_keys"
  4. Try logging in: 
    ssh yourusername@aurora.fi.muni.cz
Keep your private key safe!
Never share your private key (the id_... file without the .pub extension). If someone gets access to it, they can log into the server as you.

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