cheesy string xor'ing

xor.js

var sys = require('sys');
var L = function(str) {console.log(str)}

function xor_str(subject, key) {
    var the_res = "";
    for (i = 0; i < subject.length; i++) {
        var cur = key.charCodeAt((i % key.length));
        var c = String.fromCharCode(cur ^ subject.charCodeAt(i));
        the_res += c;
    }
    return the_res;
}

var plain = "This is some plain text...";
L("Plain text: " + plain);

var key = "ACBDBEB";

var xord = xor_str(plain, key);

L("Crypt text: " + xord);

var decrypt=  xor_str(xord, key);

L("De-crypted: " + decrypt);

Why? Because xor'ing is now part of the websocket client -> server bit masking, although the implementation is slightly more complex.