ssh-keygen error: Passphrase is too short
<p>I was trying to install hadoop on my system in which I need to configure SSH to access to localhost. But while generating the keygen using the command</p>

<blockquote>
  <p>ssh-keygen -t rsa -P --</p>
</blockquote>

<p>But while generating this keygen I got the following error</p>

<pre><code>anamika@Alex:/home/alex$ cd
anamika@Alex:~$ ssh-keygen -t rsa -P --
Generating public/private rsa key pair.
Enter file in which to save the key (/home/anamika/.ssh/id_rsa): 
Created directory '/home/anamika/.ssh'.
Saving key "/home/anamika/.ssh/id_rsa" failed: passphrase is too short(minimum five characters)
anamika@Alex:~$ exit
alex@Alex:~$ 
</code></pre>

<p>What is passphrase here? Also I tried to give some file name to save the key but still it didn't work.</p>