aes.php

<?php
/**
 * aes加密解密
 */

class MyAes
{

  private $_cipher = MCRYPT_RIJNDAEL_128;
  private $_mode = MCRYPT_MODE_CBC;

  private $_key;

  private $_initializationVectorSize;

  public function __construct ($key)
  {
    $this->_key = $key;
    $this->_initializationVectorSize = mcrypt_get_iv_size($this->_cipher, $this->_mode);
  }

  /**
   * 加密
   *
   * @param String  $data 待加密的字符串
   * @param Boolean $urlSafe 针对url是否安全
   *
   * @return String 返回加密后的数据，一般base64编码
   **/
  public function encrypt ($data, $urlSafe = false)
  {
    $data = $this->__getEncryptedStr($data);
    if ($urlSafe) {
      return $this->urlBase64Encode($data);
    }

    return base64_encode($data);
  }

  /**
   * 解密
   *
   * @param String $encryptedData 待解密字符串
   * @param Boolean $urlSafe 针对url是否安全
   *
   * @return String 返回解密后的字符串
   **/
  public function decrypt ($encryptedData, $urlSafe = false)
  {
    if ($urlSafe) {
      $encryptedData = $this->urlBase64Decode($encryptedData);
    } else {
      $encryptedData = base64_decode($encryptedData);
    }

    return $this->__getDecryptStr($encryptedData);
  }

  /**
   * 获取加密字符串
   *
   * @param String $data 待加密的数据
   *
   * @return String 加密后的数据
   **/
  private function __getEncryptedStr ($data)
  {
    $blockSize = mcrypt_get_block_size($this->_cipher, $this->_mode);
    $pad = $blockSize - (strlen($data) % $blockSize);
    $iv = mcrypt_create_iv($this->_initializationVectorSize, MCRYPT_DEV_URANDOM);

    return $iv . mcrypt_encrypt(
      $this->_cipher,
      $this->_key,
      $data . str_repeat(chr($pad), $pad),
      $this->_mode,
      $iv
    );
  }

  /**
   * 获取解密后的字符串
   *
   * @param String $encryptedData 加密后的字符串
   *
   * @return String 解密后的字符串
   **/
  private function __getDecryptStr ($encryptedData)
  {
    $initializationVector = substr($encryptedData, 0, $this->_initializationVectorSize);
    $data = mcrypt_decrypt(
      $this->_cipher,
      $this->_key,
      substr($encryptedData, $this->_initializationVectorSize),
      $this->_mode,
      $initializationVector
    );
    $pad = ord($data[strlen($data) - 1]);

    return substr($data, 0, -$pad);
  }


  /**
   * urlBase64Encode 生成URL安全的Base64编码
   *
   * @param string $bin
   *
   * @access public
   * @return string
   */
  public function urlBase64Encode ($bin)
  {
    $base64 = base64_encode($bin);
    $base64 = str_replace('+', '-', $base64);
    $base64 = str_replace('/', '_', $base64);
    $base64 = str_replace('=', '', $base64);

    return $base64;
  }

  /**
   * urlBase64Decode 解码URL安全的Base64
   *
   * @param mixed $base64
   *
   * @access public
   * @return void
   */
  public function urlBase64Decode ($base64)
  {
    $base64 = str_replace('-', '+', $base64);
    $base64 = str_replace('_', '/', $base64);
    /*
     * Put the padding back (a little tricky)
     * Base64 has one or two '=' at the end as padding.
     * 3 bytes == 4 Base64 chars
     * 1 byte left: two B64 chars and two '='
     * 2 bytes left: three B64 chars and one '='
     */
    $len = strlen($base64);
    if ($len % 4 == 2) $base64 .= '==';
    elseif ($len % 4 == 3) $base64 .= '=';

    return base64_decode($base64);
  }

}