change of instructions for ssh key

configuration.md

@@ -39,13 +39,13 @@ Check if you already have an SSH key:
 $ ls -al ~/.ssh
 ```
 <br>
-If there is a file with an extension `.pub`, you already have an SSH key.
+If there are 2 files with `id_rsa` in their name, you already have an SSH key.
 
 <div class="fragment">
 <br><br>
 If you don’t have yet an SSH key, you have to generate one:
 ```bash
-$ ssh-keygen -t rsa
+$ ssh-keygen -t rsa -b 4096
 ```
 
 <br>