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Generating a Public-Private Key Pair on Your Laptop (Linux / MAC)

Intro

You don't whisper a password through your letter box to get into your house, most people use a key.

1. Generate the Key Pair

Open the terminal on your laptop and run the following command:

ssh-keygen -t ed25519 -C "your_email@mail.dcu.ie"
  • ssh-keygen: Generates a new SSH key.
  • -t ed25519: ECDSA (using a strong curve like secp384r1 or secp521r1): Another excellent ECC-based option.
  • -C "your_email@mail.dcu.ie": Adds a label with your email address.

2. Follow the Prompts

You will be prompted for the following:

File location: Press Enter to accept the default location. Passphrase: Optionally enter a passphrase for added security.

Example:

eUser2@student:~# ssh-keygen -t ed25519 -C "student001@mail.dcu.ie"
Generating public/private ed25519 key pair.
Enter file in which to save the key (/home/student/.ssh/id_ed25519):
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /home/student/.ssh/id_ed25519
Your public key has been saved in /home/student/.ssh/id_ed25519.pub

3. Copy the Public Key

Once this is complete, you will need to copy your public key to the destination server server:

  • Output the contents of the public key just created using the following command "cat /home/student/.ssh/id_ed25519.pub"
cat ~/.ssh/id_ed25519.pub