Generating an SSH keypair with PuTTY

The first thing you need for SSH authentication using a public key is a personal key pair. This tutorial describes how to use PuTTYgen to create an RSA key pair consisting of a public key and a private key.

On Linux operating systems, the shell command ssh-keygen creates an RSA key pair consisting of the public part 'id_rsa.pub' and the private part 'id_rsa'.

Start the PuTTY utility PuTTYgen. The main window of the PuTTY Key Generator opens.
Select the type of key to be generated (in this case: SSH-2-RSA) and its bit-strength (e.g. 4096). Then click on Generate to start the key generation.
Move the mouse around in the program window until the progress bar has reached the end. PuTTYgen uses the movements of the mouse cursor within the program window to generate the random numbers necessary for key generation. After generating the keys, the program displays the key data in the main window.
PuTTYgen uses the movements of the mouse cursor within the program window to generate the random numbers necessary for key generation. Move the mouse around in the program window until the progress bar has reached the end.
Optional: If you wish to additionally protect your private key with a passphrase, enter this in the Key passphrase field and confirm in the box below it.
Please note that some SSH clients either do not store passphrases or they do it for the current session only (e.g. with PuTTY via Pageant only). For this reason you might want to avoid having to enter a passphrase where this is required manually during the process of connection establishment. LANconfig supports the persistent store of a passphrase.
You save your keys by clicking the buttons Save public key and Save private key.
The public key is stored in the device, and the private key is used in combination with PuTTY for authentication.
At the same time you can save the key as an OpenSSH private key by clicking on Conversions > Export OpenSSH key.
You can use the private key created in this way for authentication in combination with LANconfig.
Exit PuTTYgen. Now move to the next chapter of the installation.