Drupal password encryption

gistfile1.php

<?php

// Remove the asterisks with real values
$username = '2*****charity';
$hashed_password = '$S$Dk9wYRxEp7GmdP4tVn05MIlcIpzfCFH2sDsS.coi8HMnL.RtIvse';
$password = "22***VA";

if (check_password($password, $hashed_password)) {
	echo 'passes';
}
else {
	echo 'bad password';
}


function check_password($password, $hashed_password) {
  $algo = 'sha512';
  $setting = $hashed_password;

  // The first 12 characters of an existing hash are its setting string.
  $setting = substr($setting, 0, 12);

 
  $itoa64 = _password_itoa64();
  $count_log2 = strpos($itoa64, $setting[3]);

  $salt = substr($setting, 4, 8);

  // Hashes must have an 8 character salt.
  if (strlen($salt) != 8) {
    return FALSE;
  }

  // Convert the base 2 logarithm into an integer.
  $count = 1 << $count_log2;

  // We rely on the hash() function being available in PHP 5.2+.
  $hash = hash($algo, $salt . $password, TRUE);
  do {
    $hash = hash($algo, $hash . $password, TRUE);
  } while (--$count);


  $len = strlen($hash);
  $output = $setting . _password_base64_encode($hash, $len);
  // _password_base64_encode() of a 16 byte MD5 will always be 22 characters.
  // _password_base64_encode() of a 64 byte sha512 will always be 86 characters.
  $expected = 12 + ceil((8 * $len) / 6);
  $hash = (strlen($output) == $expected) ? substr($output, 0, 55) : FALSE;

  return ($hash && $hashed_password == $hash);
}
  


function _password_itoa64() {
  return './0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz';
}


function _password_base64_encode($input, $count) {
  $output = '';
  $i = 0;
  $itoa64 = _password_itoa64();
  do {
    $value = ord($input[$i++]);
    $output .= $itoa64[$value & 0x3f];
    if ($i < $count) {
      $value |= ord($input[$i]) << 8;
    }
    $output .= $itoa64[($value >> 6) & 0x3f];
    if ($i++ >= $count) {
      break;
    }
    if ($i < $count) {
      $value |= ord($input[$i]) << 16;
    }
    $output .= $itoa64[($value >> 12) & 0x3f];
    if ($i++ >= $count) {
      break;
    }
    $output .= $itoa64[($value >> 18) & 0x3f];
  } while ($i < $count);

  return $output;
}