第二種



<?php
	class MagicCrypt {
		private $iv;
		private $key;
		private $bit; //Only can use 128, 256
		function MagicCrypt($key, $bit = 128, $iv = "") {
			if($bit == 256){
				$this->key = hash('SHA256', $key, true);
			}else{
				$this->key = hash('MD5', $key, true);
			}
			if($iv != ""){
				$this->iv = hash('MD5', $iv, true);
			}else{
				$this->iv = chr(0).chr(0).chr(0).chr(0).chr(0).chr(0).chr(0).chr(0).chr(0).chr(0).chr(0).chr(0).chr(0).chr(0).chr(0).chr(0); //IV is not set. It doesn't recommend.
			}
		}
 
		function encrypt($str) {
			//Open
			$module = mcrypt_module_open(MCRYPT_RIJNDAEL_128, '', MCRYPT_MODE_CBC, '');
			mcrypt_generic_init($module, $this->key, $this->iv);
 
			//Padding
			$block = mcrypt_get_block_size(MCRYPT_RIJNDAEL_128, MCRYPT_MODE_CBC); //Get Block Size
			$pad = $block - (strlen($str) % $block); //Compute how many characters need to pad
			$str .= str_repeat(chr($pad), $pad); // After pad, the str length must be equal to block or its integer multiples
 
			//Encrypt
			$encrypted = mcrypt_generic($module, $str);
 
			//Close
			mcrypt_generic_deinit($module);
			mcrypt_module_close($module);
 
			//Return
			return base64_encode($encrypted);
		}
 
		function decrypt($str) {   
			//Open 
			$module = mcrypt_module_open(MCRYPT_RIJNDAEL_128, '', MCRYPT_MODE_CBC, '');
			mcrypt_generic_init($module, $this->key, $this->iv);
 
			//Decrypt
			$str = mdecrypt_generic($module, base64_decode($str)); //Get original str
 
			//Close
			mcrypt_generic_deinit($module);
			mcrypt_module_close($module);
 
			//Depadding
			$slast = ord(substr($str, -1)); //pad value and pad count
			$str = substr($str, 0, strlen($str) - $slast);
 
			//Return
			return $str;           
		}
	}
?>

PHP實作AES(MagicCrypt)