How to generate an SSH key pair

SSH keys allow you to securely connect to your Instances, Elastic Metal servers, and Mac minis without using a password. An SSH key consists of a key pair, which has two elements:

• An identification key (also known as a private key), which you must keep securely on the computer you want to connect from.
• A public key is uploaded to the Scaleway console, where it is displayed with a customizable name and a hash of its value, known as a fingerprint, to make it more identifiable. The public key is transferred to your Instance during the boot process for authentication.

You can generate the SSH key pair on your local machine. The process will depend on your operating system.

Before you start

To complete the actions presented below, you must have:

• A Scaleway account logged into the console
• Owner status or IAM permissions allowing you to perform actions in the intended Organization

How to generate an Ed25519 SSH key pair

How to generate an Ed25519 SSH key pair on macOS and Linux

On macOS and Linux, you can generate the SSH key pair directly from the terminal.

1. Open the terminal application by clicking on the corresponding icon.

   

2. Type the following command and press Enter to generate a new key:

   ssh-keygen -t ed25519 -C "login@example.com"
   

   Important

   It is strongly recommended to use Ed25519 for increased security and performance. If you cannot use Ed25519 keys, you can create an RSA4096 key as a fallback option:

   ssh-keygen -o -b 4096 -C "login@example.com"
   

3. When prompted to enter a file path in which to save the key, either specify a path or press Enter to accept the default location (~/.ssh/id_ed25519).

   Enter file in which to save the key (~/.ssh/id_ed25519):
   

4. Enter a passphrase when prompted. This step is optional but recommended for increased security. If you do not want to set a passphrase, press Enter directly.

   Enter passphrase (empty for no passphrase):
   

5. Confirm the passphrase by entering it again when prompted, and press Enter:

   Enter same passphrase again:
   

   The key pair will be generated in the specified filepath. The key pair consists of:

   • The public key, named id_ed25519.pub
   • The private key, named id_ed25519
   Important

   Ensure that the private key file (<key_name>) is kept secure. Do not share it with unauthorized parties. You can set appropriate permissions on the file to restrict access using the following command:

   chmod 600 <key_name>
   

6. Display the content of the public key with the following command and copy it:

   cat ~/.ssh/id_ed25519.pub
   

7. Copy the content of the public key displayed. You will need this in the next step. It should look something like this:

   ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAINPZxtCMs5sIfsMWpq7SHuqFFpBtSTmFqXWOYdf6dX4i login@example.com
   

How to generate an Ed25519 SSH key pair on Windows

On Windows, you can use the third-party application PuTTYgen to generate an SSH key pair.

1. Download and install PuTTY on your local computer. The PuTTYgen application is automatically installed along with the main PuTTY application.

   

2. Launch PuTTYgen by double-clicking the application icon.

3. Select EdDSA and click the Generate button. You can also add a passphrase before generating the key to increase security.

   

4. Move the mouse around the blank area as instructed to generate randomness.

   

   The public and private key are generated, and the following screen will display:

   

5. Complete the steps on the screen to finish:

   • Fill in the Key comment field with a name to help you identify this key pair.
   • Click the Save public key button and save it in the folder of your choice.
   • Click the Save private key button to save it in the same folder.
     Important

     Ensure that the private key file (<key_name>) is kept secure. Do not share it with unauthorized parties.

   • Select the content of the public key (the sequence of characters under “Public key for pasting into OpenSSH authorized_keys file”) and copy it, as you will need this in the next step/

How to generate a RSA SSH key pair

1. Open a terminal or command prompt on your local machine. This could be Terminal on macOS/Linux or the Command Prompt/PowerShell on Windows.

2. Run the following command to generate the RSA key pair:

   ssh-keygen -t rsa -b 4096 -C "login@example.com" -o -a 100
   

   • When prompted, enter the file in which to save the key and press Enter. If you want to save it to the default location, press Enter without typing a filename.
   • Enter a passphrase and press Enter. For added security, choose a strong passphrase.
   • Enter the same passphrase again to confirm and press Enter.

3. This command will generate two files:

   • <key_name>: The private key file (e.g., id_rsa)
   • <key_name>.pub: The public key file (e.g., id_rsa.pub)
   Important

   Ensure that the private key file (<key_name>) is kept secure. Do not share it with unauthorized parties. You can set appropriate permissions on the file to restrict access using the following command:

   chmod 600 <key_name>
   

How to upload the public SSH key to the Scaleway interface

You must upload the content of the public part of the SSH key pair you just generated to the Scaleway interface. This is then transferred to your Instance during the boot process. You can then connect and authenticate from your local machine, where your private key is stored, to the remote Instance, where the public key can be found.

1. Log into the Scaleway console, and navigate to the Credentials tab of your Project Dashboard:

   

2. Scroll down to the SSH key section, and click Add a new SSH key.

   

3. Paste the content of the public key (which you copied in the previous step) into the pop-up box, and optionally add a description. Then click Add an SSH key.

   You will now be able to connect to your Instances via SSH.