如何通过PHP实现Des加密算法代码实例(2)

class CryptDes {
 function __construct(){
  $this->key = 'codelovers'; //密钥
  $this->iv = '15548632'; //偏移量
 }
 /*
  * 加密
  */
 function encrypt($input){
  $size = mcrypt_get_block_size(MCRYPT_DES,MCRYPT_MODE_CBC); //3DES加密将MCRYPT_DES改为MCRYPT_3DES
  $input = $this->pkcs5_pad($input, $size); //如果采用PaddingPKCS7，请更换成PaddingPKCS7方法。
  $key = str_pad($this->key,8,'0'); //3DES加密将8改为24
  $td = mcrypt_module_open(MCRYPT_DES, '', MCRYPT_MODE_CBC, '');
  if( $this->iv == '' )
  {
   $iv = @mcrypt_create_iv (mcrypt_enc_get_iv_size($td), MCRYPT_RAND);
  }
  else
  {
   $iv = $this->iv;
  }
  @mcrypt_generic_init($td, $key, $iv);
  $data = mcrypt_generic($td, $input);
  mcrypt_generic_deinit($td);
  mcrypt_module_close($td);
  $data = base64_encode($data);//如需转换二进制可改成 bin2hex 转换
  return $data;
 }
 /*
  * 解密
  */
 function decrypt($encrypted){
  $encrypted = base64_decode($encrypted); //如需转换二进制可改成 bin2hex 转换
  $key = str_pad($this->key,8,'0'); //3DES加密将8改为24
  $td = mcrypt_module_open(MCRYPT_DES,'',MCRYPT_MODE_CBC,'');//3DES加密将MCRYPT_DES改为MCRYPT_3DES
  if( $this->iv == '' )
  {
   $iv = @mcrypt_create_iv (mcrypt_enc_get_iv_size($td), MCRYPT_RAND);
  }
  else
  {
   $iv = $this->iv;
  }
  $ks = mcrypt_enc_get_key_size($td);
  @mcrypt_generic_init($td, $key, $iv);
  $decrypted = mdecrypt_generic($td, $encrypted);
  mcrypt_generic_deinit($td);
  mcrypt_module_close($td);
  $y=$this->pkcs5_unpad($decrypted);
  return $y;
 }
 function pkcs5_pad ($text, $blocksize) {
  $pad = $blocksize - (strlen($text) % $blocksize);
  return $text . str_repeat(chr($pad), $pad);
 }
 function pkcs5_unpad($text){
  $pad = ord($text{strlen($text)-1});
  if ($pad > strlen($text)) {
   return false;
  }
  if (strspn($text, chr($pad), strlen($text) - $pad) != $pad){
   return false;
  }
  return substr($text, 0, -1 * $pad);
 }
 function PaddingPKCS7($data) {
  $block_size = mcrypt_get_block_size(MCRYPT_DES, MCRYPT_MODE_CBC);//3DES加密将MCRYPT_DES改为MCRYPT_3DES
  $padding_char = $block_size - (strlen($data) % $block_size);
  $data .= str_repeat(chr($padding_char),$padding_char);
  return $data;
 }
}