PHP实现AES256加密算法实例(4)

/* aes 256 encrypt 
* @param String $ostr 
* @param String $securekey 
* @param String $type encrypt, decrypt 
*/ 
function aes($ostr, $securekey, $type='encrypt'){ 
  if($ostr==''){ 
    return ''; 
  } 
   
  $key = $securekey; 
  $iv = strrev($securekey); 
  $td = mcrypt_module_open('rijndael-256', '', 'ofb', ''); 
  mcrypt_generic_init($td, $key, $iv); 
 
  $str = ''; 
 
  switch($type){ 
    case 'encrypt': 
      $str = base64_encode(mcrypt_generic($td, $ostr)); 
      break; 
 
    case 'decrypt': 
      $str = mdecrypt_generic($td, base64_decode($ostr)); 
      break; 
  } 
 
  mcrypt_generic_deinit($td); 
 
  return $str; 
} 
 
// Demo 
$key = "fdipzone201314showmethemoney!@#$"; 
$str = "show me the money"; 
 
$ostr = aes($str, $key); 
echo "String 1: $ostr<br />"; 
 
$dstr = aes($ostr, $key, 'decrypt'); 
echo "String 2: $dstr<br />";