PuTTY with SSH key tutorial

This tutorial shows how to generate a new SSH key, then configure a PuTTY session to use it.

What's this?

To login to the server, instead of a password, you use a key.

This key is divided in two parts:

the public key, you give freely (you can publish it on your webpage for example) where you need to have an access
the private key, you keep very safely and privately for you and only you

The public key is more like a login, the privave key more like a password.

PuTTY ships a software to generate a key, PuTTYGen. You can download it on http://www.chiark.greenend.org.uk/~sgtatham/putty/download.html.

Step 1. Run it, and you've this screen. Click on the generate button.

Step 2. Move the mouse to generate some randomness. That will be used to generate a random key, a key we can't guess.

Step 3. Copy/paste the content of first textarea (ssh-rsa ...): this is your public key.

Save safely where you want the key ("Save private key").

If you set a password, the key will be encrypted, and a password asked each time you use the key.