title: Which hashing algorithm is used by PHP session.hash_function mixed as default
body: <p>Which hashing algorithm is used by PHP  session.hash_function as default?
  The following page says that default is md5 "0":
  <a href="http://php.net/manual/en/session.configuration.php#ini.session.hash-function" rel="nofollow">http://php.net/manual/en/session.configuration.php#ini.session.hash-function</a>
  However the hash algo page shows code "0" to be md2.
  <a href="http://php.net/manual/en/function.hash-algos.php" rel="nofollow">http://php.net/manual/en/function.hash-algos.php</a></p>
  
  <p>If code "0" on php.ini really corresponds to md5 then what are the codes for other hash algorithms for php.ini ? For example what is the code for sha512?</p>