php结合md5的加密解密算法实例

<?php/** Created on 2016-9-30**/function encrypt($data, $key){ $key = md5($key);  $x = 0;  $len = strlen($data);  $l = strlen($key);  for ($i = 0; $i < $len; $i++)  {    if ($x == $l)    {     $x = 0;    }    $char .= $key{$x};    $x++;  }  for ($i = 0; $i < $len; $i++)  {    $str .= chr(ord($data{$i}) + (ord($char{$i})) % 256);  }  return base64_encode($str);}function decrypt($data, $key){ $key = md5($key);  $x = 0;  $data = base64_decode($data);  $len = strlen($data);  $l = strlen($key);  for ($i = 0; $i < $len; $i++)  {    if ($x == $l)    {     $x = 0;    }    $char .= substr($key, $x, 1);    $x++;  }  for ($i = 0; $i < $len; $i++)  {    if (ord(substr($data, $i, 1)) < ord(substr($char, $i, 1)))    {      $str .= chr((ord(substr($data, $i, 1)) + 256) - ord(substr($char, $i, 1)));    }    else    {      $str .= chr(ord(substr($data, $i, 1)) - ord(substr($char, $i, 1)));    }  }  return $str;}$data = 'VeVb武林网www.vevb.com'; // 被加密信息$data=iconv("gbk","utf-8",$data);$key = 'www.vevb.com';   // 密钥$encrypt = encrypt($data, $key);$decrypt = decrypt($encrypt, $key);echo $encrypt, "<br/>", $decrypt;?>

TrXMTM8SFB3DGhTr2qeuYqOXZmpmn8moVeVb武林网www.vevb.com