Base64 encryption decrypts a piece of PHP encryption and decryption code

$key = "This was supposed to be a secret key!!!";
function KeyED ($txt, $encrypt _key)
{
$encrypt _key = MD5 ($encrypt _key);
$ctr = 0;
$tmp = "";
for ($i =0; $i {
if ($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; $i {
if ($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 {
$md 5 = substr ($txt, $i, 1);
$i + +;
$tmp. = (substr ($txt, $i, 1) ^ $md 5);
}
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
N";
Print "Encrypted text: $enc _text
N";
Print "decrypted text: $dec _text
N";
?>

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