<?php
/**
 * Class AES
 * 用于AES加解密数据
 * time:2018-04-27
 */
class AES
{
  protected $cipher = MCRYPT_RIJNDAEL_256; //AES加密算法
  protected $mode = MCRYPT_MODE_CBC; //采用cbc加密模式
  protected $key; //密钥
  protected $iv; //cbc模式加密向量，如为空将采用密钥代替
  /**
   * AES constructor.
   *
   * @param   $key 密钥
   * @param null $iv 向量 可选 如为空将采用密钥代替
   *
   * @throws Exception
   */
  public function __construct($key, $iv = NULL)
  {
    if (!extension_loaded("mcrypt")) {
//      throw new \Exception("mcrypt extension do not exist. it was DEPRECATED in PHP 7.1.0, and REMOVED in PHP 7.2.0. use OpenSSL instead");
    }
    $this->key = $key;
    $this->iv = $iv;
  }
  /**
   * 加密数据
   * @param $data
   *
   * @return string
   */
  public function encrypt($data)
  {
    $td = mcrypt_module_open($this->cipher, '', $this->mode, '');
    $key = hash("sha256", $this->key, true);
    $iv = isset($this->iv) ? hash("sha256", $this->iv, true) : $key;
    $data = $this->padding($data);
    mcrypt_generic_init($td, $key, $iv);
    $encryptedData = base64_encode(mcrypt_generic($td, $data));
    mcrypt_generic_deinit($td);
    mcrypt_module_close($td);
    return $encryptedData;
  }
  /**
   * 解密数据
   * @param $data
   *
   * @return bool|string
   */
  public function decrypt($data)
  {
    $td = mcrypt_module_open($this->cipher, '', $this->mode, '');
    $key = hash("sha256", $this->key, true);
    $iv = isset($this->iv) ? hash("sha256", $this->iv, true) : $key;
    mcrypt_generic_init($td, $key, $iv);
    $decrypted_data = mdecrypt_generic($td, base64_decode($data));
    mcrypt_generic_deinit($td);
    mcrypt_module_close($td);
    return $this->unPadding($decrypted_data);
  }
  /**
   * 填充数据到分组大小的整数倍
   * @param null $data
   *
   * @return string
   */
  protected function padding($data = null)
  {
    $blockSize = 32; //MCRYPT_RIJNDAEL_256算法的分组大小是32字节
    $pad = $blockSize - (strlen($data) % $blockSize);
    return $data . str_repeat(chr($pad), $pad);
  }
  /**
   * 去掉填充的数据
   * @param null $data
   *
   * @return bool|string
   */
  protected function unPadding($data = null)
  {
    $pad = ord($data[strlen($data) - 1]);
    if ($pad > strlen($data)) {
      return false;
    }
    if (strspn($data, chr($pad), strlen($data) - $pad) != $pad) {
      return false;
    }
    return substr($data, 0, -1 * $pad);
  }
  /**
   * @return mixed
   */
  public function getSecretKey()
  {
    return $this->key;
  }
  /**
   * @param mixed $key
   */
  public function setSecretKey($key)
  {
    $this->key = $key;
  }
  /**
   * @return null
   */
  public function getIv()
  {
    return $this->iv;
  }
  /**
   * @param null $iv
   */
  public function setIv($iv)
  {
    $this->iv = $iv;
  }
}
//使用方法：
$keyStr = 'sq8f77fwhksk';
$aes = new AES($keyStr);
$str = 'www.jb51.net';
$chgstr = $aes->encrypt($str);
echo $chgstr;
echo "<br/>";
$rstr = $aes->decrypt($chgstr);
echo $rstr;
?>