<?php
$id = "https://www.ofstack.com";
$token = encrypt($id, 'E', 'jb51');
echo ' encryption :'.encrypt($id, 'E', 'jb51');
echo '<br />';
echo ' Decryption: '.encrypt($token, 'D', 'jb51');
/*********************************************************************
The name of the function :encrypt
Function are : Encrypt and decrypt string
Method of use :
encryption :encrypt('str','E','qingdou');
decryption :encrypt(' An encrypted string ','D','qingdou');
Parameters that :
$string : String that needs to be encrypted and decrypted
$operation: Determine whether to encrypt or decrypt :E: encryption D: decryption
$key : Encrypted key ( The key );
*********************************************************************/
function encrypt($string,$operation,$key='')
{
$src = array("/","+","=");
$dist = array("_a","_b","_c");
if($operation=='D'){$string = str_replace($dist,$src,$string);}
$key=md5($key);
$key_length=strlen($key);
$string=$operation=='D'?base64_decode($string):substr(md5($string.$key),0,8).$string;
$string_length=strlen($string);
$rndkey=$box=array();
$result='';
for($i=0;$i<=255;$i++)
{
$rndkey[$i]=ord($key[$i%$key_length]);
$box[$i]=$i;
}
for($j=$i=0;$i<256;$i++)
{
$j=($j+$box[$i]+$rndkey[$i])%256;
$tmp=$box[$i];
$box[$i]=$box[$j];
$box[$j]=$tmp;
}
for($a=$j=$i=0;$i<$string_length;$i++)
{
$a=($a+1)%256;
$j=($j+$box[$a])%256;
$tmp=$box[$a];
$box[$a]=$box[$j];
$box[$j]=$tmp;
$result.=chr(ord($string[$i])^($box[($box[$a]+$box[$j])%256]));
}
if($operation=='D')
{
if(substr($result,0,8)==substr(md5(substr($result,8).$key),0,8))
{
return substr($result,8);
}
else
{
return'';
}
}
else
{
$rdate = str_replace('=','',base64_encode($result));
$rdate = str_replace($src,$dist,$rdate);
return $rdate;
}
}
?>