<?php

class MagicCrypt {
	private $iv = "0102030405060708";//密钥偏移量IV，可自定义

	private $encryptKey = "自定义16位长度key";//AESkey，可自定义

	//加密
	public function encrypt($encryptStr) {
		$localIV = $this->iv;
		$encryptKey = $this->encryptKey;

		//Open module
		$module = mcrypt_module_open(MCRYPT_RIJNDAEL_128, '', MCRYPT_MODE_CBC, $localIV);

		//print "module = $module <br/>" ;

		mcrypt_generic_init($module, $encryptKey, $localIV);

		//Padding
		$block = mcrypt_get_block_size(MCRYPT_RIJNDAEL_128, MCRYPT_MODE_CBC);
		$pad = $block - (strlen($encryptStr) % $block); //Compute how many characters need to pad
		$encryptStr .= str_repeat(chr($pad), $pad); // After pad, the str length must be equal to block or its integer multiples

		//encrypt
		$encrypted = mcrypt_generic($module, $encryptStr);

		//Close
		mcrypt_generic_deinit($module);
		mcrypt_module_close($module);

		return base64_encode($encrypted);

	}

	//解密
	public function decrypt($encryptStr) {
		$localIV = $this->iv;
		$encryptKey = $this->encryptKey;

		//Open module
		$module = mcrypt_module_open(MCRYPT_RIJNDAEL_128, '', MCRYPT_MODE_CBC, $localIV);

		//print "module = $module <br/>" ;

		mcrypt_generic_init($module, $encryptKey, $localIV);

		$encryptedData = base64_decode($encryptStr);
		$encryptedData = mdecrypt_generic($module, $encryptedData);

		return $encryptedData;
	}
}
$encryptString = 'gz1DR+BsCzQe55HFdq1IiQ==';
$encryptObj = new MagicCrypt();

$result = $encryptObj->encrypt($encryptString);//加密结果
$decryptString = $decryptString = $encryptObj->decrypt($result);//解密结果
echo $result . "<br/>";
echo $decryptString . "<br/>";
?>