Generating an ssh Key

PlanetLab uses 1024bit RSA keys for authentication. Access to resources is secured through public key encryption. Before you can access any PlanetLab Europe nodes, including those at your own site, you must create an SSH key pair for authentication purposes. You must upload your public ssh key to use PlanetLab. You can generate an ssh key using OpenSSH or PuTTY.

To generate an ssh key using OpenSSH:

ssh-keygen -t rsa -f ~/.ssh/id_planetlab

This key must be in OpenSSH format. If the system is running a commercial UNIX and the first line of your .pub file does not look like

ssh-rsa AAAAB3Nza...

you need to convert your key. Consult the documentation that comes with the version of ssh-keygen that you are using.

ssh-keygen asks for a passphrase. Good passphrases are 10-30 characters long and are not simple sentences or otherwise easily guessable. ssh-keygen will generate two files: a private key file named id_rsa and a public key file named id_rsa.pub. Store the private key file id_rsa in a safe place, such as on a removable USB flash memory device. Upload the public key file id_rsa.pub to the PlanetLab website using the Manage My Keys page.

Protect your private key file! If your private key file is stolen and your account used for illegal activity, your site and PI may be held legally responsible. If you lose your private key file or suspect that it has been stolen or otherwise compromised, generate a new key pair with a new passphrase, upload the new public key to the website, and notify PlanetLab Support immediately.

If you do not have an ssh client, you need to install one. PuTTY is the preferred client. You can download the Windows installer from the PuTTY web site.

To generate an ssh key using PuTTY

  1. Navigate to PuTTY Download Page
  2. Download puttygen.exe using a standard file download procedure
  3. Run the puttygen.exe utility to generate a pair of private/public keys. The PuTTY Key Generator window opens.

    4. Note: Make sure the SSH-2 RSA parameter is selected.

  4. Click Generate
  5. Generate some randomness by moving the mouse around the blank area. Once you have accumulated enough entropy, the application generates the key.
  6. Enter a lengthy passphrase in the Key passphrase field
  7. Confirm it in the Confirm passphrase field
  8. Click on the Save Private Key button to save your private key in a file.
    With your mouse, select the content of the box labeled Public Key for pasting into OpenSSH authorized_keys file, copy it (that is, hit Control-C).
  9. Paste this into a new file with the extension .pub.

    10. This .pub file can now be uploaded to PlanetLab. Now, when trying to access a node for the first time, you first need to select the putty configuration option under SSH -> Auth Set the "Private Key file for authentication" to the .ppk file you created in the first step.

    Browse to locate key file

  10. Select key
  11. Click Upload