[PHP]代码

<?php   //blog.qita.in  function passport_encrypt($txt, $key) {   srand((double)microtime() * 1000000);   $encrypt_key = md5(rand(0, 32000));   $ctr = 0;   $tmp = '';   for($i = 0;$i < strlen($txt); $i++) {   $ctr = $ctr == strlen($encrypt_key) ? 0 : $ctr;   $tmp .= $encrypt_key[$ctr].($txt[$i] ^ $encrypt_key[$ctr++]);   }   return base64_encode(passport_key($tmp, $key));   }  function passport_decrypt($txt, $key) {   $txt = passport_key(base64_decode($txt), $key);   $tmp = '';   for($i = 0;$i < strlen($txt); $i++) {   $md5 = $txt[$i];   $tmp .= $txt[++$i] ^ $md5;   }   return $tmp;   }  function passport_key($txt, $encrypt_key) {   $encrypt_key = md5($encrypt_key);   $ctr = 0;   $tmp = '';   for($i = 0; $i < strlen($txt); $i++) {   $ctr = $ctr == strlen($encrypt_key) ? 0 : $ctr;   $tmp .= $txt[$i] ^ $encrypt_key[$ctr++];   }   return $tmp;   }   ?>