<?php

$key = "This is supposed to be a secret key !!!";



function keyED($txt,$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;

}



function encrypt($txt,$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++;

}

return keyED($tmp,$key);

}



function decrypt($txt,$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 = "Hello World !!!";



// encrypt $string, and store it in $enc_text

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



// decrypt the encrypted text $enc_text, and store it in $dec_text

$dec_text = decrypt($enc_text,$key);



print "Original text : $string <Br>n";

print "Encrypted text : $enc_text <Br>n";

print "Decrypted text : $dec_text <Br>n";

?>