<?php
$key="Thisissupposedtobeasecretkey!!!";

functionkeyED($txt,$encrypt_key)
{
$encrypt_key=md5($encrypt_key);
$ctr=0;
$tmp="";
for($i=0;$i<strlen($txt);$i++)
{
if($ctr==strlen($encrypt_key))$ctr=0;
$tmp.=substr($txt,$i,1)^substr($encrypt_key,$ctr,1);
$ctr++;
}
return$tmp;
}

functionencrypt($txt,$key)
{
srand((double)microtime()*1000000);
$encrypt_key=md5(rand(0,32000));
$ctr=0;
$tmp="";
for($i=0;$i<strlen($txt);$i++)
{
if($ctr==strlen($encrypt_key))$ctr=0;
$tmp.=substr($encrypt_key,$ctr,1).
(substr($txt,$i,1)^substr($encrypt_key,$ctr,1));
$ctr++;
}
returnkeyED($tmp,$key);
}

functiondecrypt($txt,$key)
{
$txt=keyED($txt,$key);
$tmp="";
for($i=0;$i<strlen($txt);$i++)
{
$md5=substr($txt,$i,1);
$i++;
$tmp.=(substr($txt,$i,1)^$md5);
}
return$tmp;
}

$string="HelloWorld!!!";

//encrypt$string,andstoreitin$enc_text
$enc_text=encrypt($string,$key);

//decrypttheencryptedtext$enc_text,andstoreitin$dec_text
$dec_text=decrypt($enc_text,$key);

print"Originaltext:$string<Br>n";
print"Encryptedtext:$enc_text<Br>n";
print"Decryptedtext:$dec_text<Br>n";
?>