jCryption javascript data encryption

<?php
session_start();
require_once("jCryption-1.0.1.php");
 
$keyLength = 256;
$jCryption = new jCryption();
 
if(isset($_GET["generateKeypair"])) {
	$keys = $jCryption->generateKeypair($keyLength);
 
	//sets the keys in the session to have them ready when you submit the form
	//please keep this structure. You'll need the hex value of the key for javascript
	//and the int value of the key for PHP. e = public key, d = private key, n = modulo
	$_SESSION["e"] = array("int" => $keys["e"], "hex" => $jCryption->dec2string($keys["e"],16));
	$_SESSION["d"] = array("int" => $keys["d"], "hex" => $jCryption->dec2string($keys["d"],16));
	$_SESSION["n"] = array("int" => $keys["n"], "hex" => $jCryption->dec2string($keys["n"],16));
 
	//returns the needed keys for the javascript part in a JSON string
	//maxdigits is need for the javascript and caluclated like ($keyLength * 2 / 16 + 3)
	echo '{"e":"'.$_SESSION["e"]["hex"].'","n":"'.$_SESSION["n"]["hex"].'","maxdigits":"'.intval($keyLength*2/16+3)).'"}';
} else {
	//print the orginial POST
	echo "POST:";
	print_r($_POST);
	echo "<br/>";
 
	//here the decrypt function is called. The first parameter is the encrypted POST.
	//Second parameter is the private key d in it's int form and third the modulo n.
	//This function will return your orginal decrypted POST.
	$var = $jCryption->decrypt($_POST['jCryption'], $_SESSION["d"]["int"], $_SESSION["n"]["int"]);
	//parses the decrypted string and returns it in an array.
	//now it's important to unset the keys from the session
	unset($_SESSION["e"]);
	unset($_SESSION["d"]);
	unset($_SESSION["n"]);
	parse_str($var,$result);
	echo "decrypted POST";
	print_r($result);
}
?>