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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

Você pode acessar e gravar dados em repositórios em dados GitHub.com usando o SSH (Protocolo Secure Shell). Ao se conectar por meio do SSH, você se autentica usando um arquivo de chave privada no computador local. 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 Cloud, 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 GitHub.com to enable authentication for Git operations over SSH.

Observação: o GitHub aprimorou a segurança removendo tipos de chaves mais antigos e não seguros em 15 de março de 2022.

Desde essa data, não há mais suporte para as chaves DSA (ssh-dss). Não é possível adicionar novas chaves DSA à sua conta pessoal do GitHub.com.

As chaves RSA (ssh-rsa) com um valid_after antes de 2 de novembro de 2021 podem continuar usando qualquer algoritmo de assinatura. As chaves RSA geradas após essa data precisam usar um algoritmo de assinatura SHA-2. Talvez alguns clientes mais antigos precisem ser atualizados para usar as assinaturas SHA-2.

  1. Abra TerminalTerminalGit Bash.

  2. Paste the text below, substituting in your GitHub Enterprise Cloud 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.
  3. When you're prompted to "Enter a file in which to save the key," press Enter. This accepts the default file location.

    > Enter a file in which to save the key (/Users/you/.ssh/id_algorithm): [Press enter]
    > Enter a file in which to save the key (/c/Users/you/.ssh/id_algorithm):[Press enter]
    > Enter a file in which to save the key (/home/you/.ssh/algorithm): [Press enter]
  4. 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. When adding your SSH key to the agent, use the default macOS ssh-add command, and not an application installed by macports, homebrew, or some other external source.

  1. Inicie o ssh-agent em segundo plano.

    $ eval "$(ssh-agent -s)"
    > Agent pid 59566

    Dependendo do seu ambiente, talvez seja necessário usar um comando diferente. Por exemplo, talvez seja necessário usar o acesso raiz executando sudo -s -H antes de iniciar o ssh-agent ou usar exec ssh-agent bash ou exec ssh-agent zsh para executar o ssh-agent.

  2. If you're using macOS Sierra 10.12.2 or later, you will need to modify your ~/.ssh/config file to automatically load keys into the ssh-agent and store passphrases in your keychain.

    • First, check to see if your ~/.ssh/config file exists in the default location.

      $ open ~/.ssh/config
      > The file /Users/you/.ssh/config does not exist.
    • If the file doesn't exist, create the file.

      $ touch ~/.ssh/config
    • Open your ~/.ssh/config file, then modify the file to contain the following lines. If your SSH key file has a different name or path than the example code, modify the filename or path to match your current setup.

      Host *
        AddKeysToAgent yes
        UseKeychain yes
        IdentityFile ~/.ssh/id_ed25519
      

      Notes:

      • If you chose not to add a passphrase to your key, you should omit the UseKeychain line.

      • If you see a Bad configuration option: usekeychain error, add an additional line to the configuration's' Host * section.

        Host *
          IgnoreUnknown UseKeychain
        
  3. Add your SSH private key to the ssh-agent and store your passphrase in the keychain. Se você criou sua chave com um nome diferente ou se estiver adicionando uma chave existente que tenha outro nome, substitua id_ed25519 no comando pelo nome do arquivo de chave privada.

    $ ssh-add -K ~/.ssh/id_ed25519

    Note: The -K option is Apple's standard version of ssh-add, which stores the passphrase in your keychain for you when you add an SSH key to the ssh-agent. If you chose not to add a passphrase to your key, run the command without the -K option.

    If you don't have Apple's standard version installed, you may receive an error. For more information on resolving this error, see "Error: ssh-add: illegal option -- K."

    In MacOS Monterey (12.0), the -K and -A flags are deprecated and have been replaced by the --apple-use-keychain and --apple-load-keychain flags, respectively.

  4. Add the SSH key to your account on GitHub Enterprise Cloud. For more information, see "Adding a new SSH key to your GitHub account."

Se você tiver o GitHub Desktop instalado, poderá usá-lo para clonar repositórios e não lidar com chaves SSH.

  1. Ensure the ssh-agent is running. You can use the "Auto-launching the ssh-agent" instructions in "Working with SSH key passphrases", or start it manually:

    # start the ssh-agent in the background
    $ eval "$(ssh-agent -s)"
    > Agent pid 59566
  2. Add your SSH private key to the ssh-agent. Se você criou sua chave com um nome diferente ou se estiver adicionando uma chave existente que tenha outro nome, substitua id_ed25519 no comando pelo nome do arquivo de chave privada.

    $ ssh-add ~/.ssh/id_ed25519
  3. Add the SSH key to your account on GitHub Enterprise Cloud. For more information, see "Adding a new SSH key to your GitHub account."

  1. Inicie o ssh-agent em segundo plano.

    $ eval "$(ssh-agent -s)"
    > Agent pid 59566

    Dependendo do seu ambiente, talvez seja necessário usar um comando diferente. Por exemplo, talvez seja necessário usar o acesso raiz executando sudo -s -H antes de iniciar o ssh-agent ou usar exec ssh-agent bash ou exec ssh-agent zsh para executar o ssh-agent.

  2. Add your SSH private key to the ssh-agent. Se você criou sua chave com um nome diferente ou se estiver adicionando uma chave existente que tenha outro nome, substitua id_ed25519 no comando pelo nome do arquivo de chave privada.

    $ ssh-add ~/.ssh/id_ed25519
  3. Add the SSH key to your account on GitHub Enterprise Cloud. For more information, see "Adding a new SSH key to your GitHub account."

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. Abra TerminalTerminalGit Bash.

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

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

    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.

    > Enter a file in which to save the key (/Users/you/.ssh/id_ed25519_sk): [Press enter]
    > Enter a file in which to save the key (/c/Users/you/.ssh/id_ed25519_sk):[Press enter]
    > Enter a file in which to save the key (/home/you/.ssh/id_ed25519_sk): [Press enter]
  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."