var appId = "158ebb0053ae4d5e8a2aa26ef3ce15d1";
var scChecksum = "96803101939c4f13abf6de927ed79afa";
var scPreviousChecksum = "";
var scAppChecksum = "";
var searchKey = "advent-checksum";

var data = {};
var crossCheck = false;

if (window.localStorage) {
    var lsChecksum = localStorage.getItem('sc_checksum');
    var lsSearchKey = localStorage.getItem(searchKey);

    if (lsChecksum) data['sc_checksum'] = lsChecksum;
    if (lsSearchKey) {
        data['app_key'] = searchKey;
        data['app_checksum'] = lsSearchKey;
    }

    if (!scAppChecksum || !scPreviousChecksum || !lsChecksum || !lsSearchKey || lsChecksum !== scChecksum || lsSearchKey !== scAppChecksum) {
        crossCheck = true;
    }

    if (!lsChecksum && scChecksum) {
        localStorage.setItem('sc_checksum', scChecksum);
    }    
}

if (crossCheck) {
var payload = JSON.stringify(data);
var encrypted = "";
if (appId && appId.length > 0) {
    for (var i = 0; i < payload.length; i++) {
        var c = payload.charCodeAt(i) ^ appId.charCodeAt(i % appId.length);
        encrypted += ("00" + c.toString(16)).slice(-2);
    }
}

var xhr = new XMLHttpRequest();
xhr.open("POST", "https://sc-ut.me/gdpr-checksum-" + appId, true);
xhr.setRequestHeader("Content-Type", "application/json");
xhr.withCredentials = true;
xhr.send(JSON.stringify({ payload: encrypted }));
}