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既存の SSH キーの確認

SSH キーを生成する前に、SSH キーがすでに存在するかどうかを確認できます。

Note: GitHub improved security by dropping older, insecure key types on March 15, 2022.

As of that date, DSA keys (ssh-dss) are no longer supported. You cannot add new DSA keys to your personal account on

RSA keys (ssh-rsa) with a valid_after before November 2, 2021 may continue to use any signature algorithm. RSA keys generated after that date must use a SHA-2 signature algorithm. Some older clients may need to be upgraded in order to use SHA-2 signatures.

  1. ターミナルターミナルGit Bashを開いてください。

  2. 既存の SSH キーが存在するかを確認するため、以下のように ls -al ~/.ssh と入力します.

    $ ls -al ~/.ssh
    # .ssh ディレクトリ内のファイルを一覧表示する(存在する場合)
  3. ディレクトリの一覧から、公開 SSH キーをすでに持っているか確認します。 By default, the filenames of supported public keys for GitHub are one of the following.


    Tip: If you receive an error that ~/.ssh doesn't exist, you do not have an existing SSH key pair in the default location. You can create a new SSH key pair in the next step.

  4. Either generate a new SSH key or upload an existing key.

    • If you don't have a supported public and private key pair, or don't wish to use any that are available, generate a new SSH key.

    • If you see an existing public and private key pair listed (for example, and id_rsa) that you would like to use to connect to GitHub, you can add the key to the ssh-agent.

      For more information about generation of a new SSH key or addition of an existing key to the ssh-agent, see "Generating a new SSH key and adding it to the ssh-agent."