title: Hash value always different on same input
body: <p>I'm trying to use <a href="https://github.com/ircmaxell/password_compat" rel="noreferrer">this hashing function</a> but each time I reload the page it gives me a different string, except for the first 7 characters. </p>
  
  <pre><code>&lt;?php  
  require("lib/password.php")  
  $pass = $_POST['input_password'];
  echo 'Received: '.$pass.'&lt;br /&gt;';
  $passwordHash = 'default';   
  $passwordHash = password_hash(trim($pass), PASSWORD_DEFAULT, ["cost" =&gt; 11]);   
  echo 'Password hash is '.$passwordHash;  
  </code></pre>
  
  <p>For example I pass over aaa and get the hashes</p>
  
  <pre><code>$2y$11$1Ll4twbmFNWhVxBOCeDWhOtZ4WchW.GYXK3LSH9BnW6AhXf45soWq
  $2y$11$H0dmOkkq3rSgggDbGueRPusODmkZrrFqG7I/R1B0tFTQEYGHB0iZi
  $2y$11$z0pFOoFsD5Bk0sx2TiT3kOd2awAwDBQAsQaxlDq11kNH.ldaS1qw2
  </code></pre>
  
  <p>I'm using WAMP Server 2.2 on Windows 7 64 bit and Firefox 17.</p>