Generating Multiple SSH Key Pairs

SSH key pairs are used for secure access to remote servers. You might need multiple key pairs for different purposes or services. Here's a short guide on generating unique SSH key pairs.

Step 1: Open a Terminal

Open your terminal application. This process works on Linux, macOS, and Windows (using Git Bash or WSL).

Step 2: Generate a New SSH Key Pair

Use the ssh-keygen command to generate a new key pair. You can specify a unique name for each key pair to avoid overwriting existing ones.

ssh-keygen -t rsa -b 4096 -f ~/.ssh/id_rsa_unique

Explanation:

• -t rsa: Specifies the type of key to create, in this case, RSA.
• -b 4096: Specifies the number of bits in the key (4096 bits).
• -f ~/.ssh/id_rsa_unique: Specifies the file name and location for the new key pair.

Step 3: Enter a Passphrase (Optional)

You will be prompted to enter a passphrase. This adds an extra layer of security. You can press Enter to skip this step if you don't want to set a passphrase.

Enter passphrase (empty for no passphrase):
Enter same passphrase again:

Step 4: View Your Key Pair

Your new SSH key pair will be saved in the specified location (~/.ssh/id_rsa_unique and ~/.ssh/id_rsa_unique.pub).

To view your public key, use:

cat ~/.ssh/id_rsa_unique.pub

Step 5: Add Your SSH Key to the SSH Agent

Start the SSH agent and add your new SSH key.

eval "$(ssh-agent -s)"
ssh-add ~/.ssh/id_rsa_unique

Step 6: Add the Public Key to Remote Servers

Copy the content of your public key (~/.ssh/id_rsa_unique.pub) and add it to the ~/.ssh/authorized_keys file on the remote server you want to access.

You can use ssh-copy-id to do this easily:

ssh-copy-id -i ~/.ssh/id_rsa_unique.pub username@remote_host

Step 7: Update SSH Config (Optional)

To manage multiple SSH keys more easily, you can create or edit the SSH config file (~/.ssh/config) to specify which key to use for each host.

nano ~/.ssh/config

Add the following configuration:

Host remote_host_alias
    HostName remote_host
    User username
    IdentityFile ~/.ssh/id_rsa_unique

Step 8: Connect Using Your SSH Key

Now you can connect to your remote server using the alias you defined in the SSH config file.

ssh remote_host_alias

Summary

You have generated a unique SSH key pair, added it to your SSH agent, configured it for a specific remote server, and optionally updated your SSH config for easier access. Repeat the above steps with different filenames to create multiple unique SSH key pairs as needed.