Skip to main content

This version of GitHub Enterprise was discontinued on 2022-10-12. No patch releases will be made, even for critical security issues. For better performance, improved security, and new features, upgrade to the latest version of GitHub Enterprise. For help with the upgrade, contact GitHub Enterprise support.

Generating a new SSH key and adding it to the ssh-agent

After you've checked for existing SSH keys, you can generate a new SSH key to use for authentication, then add it to the ssh-agent.

About SSH key passphrases

You can access and write data in repositories on your GitHub Enterprise Server instance using SSH (Secure Shell Protocol). When you connect via SSH, you authenticate using a private key file on your local machine. For more information, see "About SSH."

When you generate an SSH key, you can add a passphrase to further secure the key. Whenever you use the key, you must enter the passphrase. If your key has a passphrase and you don't want to enter the passphrase every time you use the key, you can add your key to the SSH agent. The SSH agent manages your SSH keys and remembers your passphrase.

If you don't already have an SSH key, you must generate a new SSH key to use for authentication. If you're unsure whether you already have an SSH key, you can check for existing keys. For more information, see "Checking for existing SSH keys."

If you want to use a hardware security key to authenticate to GitHub Enterprise Server, you must generate a new SSH key for your hardware security key. You must connect your hardware security key to your computer when you authenticate with the key pair. For more information, see the OpenSSH 8.2 release notes.

Generating a new SSH key

You can generate a new SSH key on your local machine. After you generate the key, you can add the key to your account on your GitHub Enterprise Server instance to enable authentication for Git operations over SSH.

If you are a site administrator for your GitHub Enterprise Server instance, you can use the same key to grant yourself administrative SSH access to the instance. For more information, see "Accessing the administrative shell (SSH)."

  1. Open .

  2. Paste the text below, substituting in your GitHub Enterprise Server email address.

    $ ssh-keygen -t ed25519 -C "your_email@example.com"

    Note: If you are using a legacy system that doesn't support the Ed25519 algorithm, use:

    $ ssh-keygen -t rsa -b 4096 -C "your_email@example.com"

    This creates a new SSH key, using the provided email as a label.

    > Generating public/private ALGORITHM key pair.

    When you're prompted to "Enter a file in which to save the key", you can press Enter to accept the default file location. Please note that if you created SSH keys previously, ssh-keygen may ask you to rewrite another key, in which case we recommend creating a custom-named SSH key. To do so, type the default file location and replace id_ssh_keyname with your custom key name.

  3. At the prompt, type a secure passphrase. For more information, see "Working with SSH key passphrases."

    > Enter passphrase (empty for no passphrase): [Type a passphrase]
    > Enter same passphrase again: [Type passphrase again]

Adding your SSH key to the ssh-agent

Before adding a new SSH key to the ssh-agent to manage your keys, you should have checked for existing SSH keys and generated a new SSH key.

Generating a new SSH key for a hardware security key

If you are using macOS or Linux, you may need to update your SSH client or install a new SSH client prior to generating a new SSH key. For more information, see "Error: Unknown key type."

  1. Insert your hardware security key into your computer.

  2. Open .

  3. Paste the text below, substituting in the email address for your account on GitHub Enterprise Server.

    $ ssh-keygen -t ed25519-sk -C "YOUR_EMAIL"

    Note: If the command fails and you receive the error invalid format or feature not supported, you may be using a hardware security key that does not support the Ed25519 algorithm. Enter the following command instead.

    $ ssh-keygen -t ecdsa-sk -C "your_email@example.com"
  4. When you are prompted, touch the button on your hardware security key.

  5. When you are prompted to "Enter a file in which to save the key," press Enter to accept the default file location.

  6. When you are prompted to type a passphrase, press Enter.

    > Enter passphrase (empty for no passphrase): [Type a passphrase]
    > Enter same passphrase again: [Type passphrase again]
  7. Add the SSH key to your account on GitHub. For more information, see "Adding a new SSH key to your GitHub account."