function en(key, str) {
	var res = "";   
	for (i = 0, j = 0; i < str.length; i++) { 
		res = res + String.fromCharCode(str.charCodeAt(i) ^ key.charCodeAt(j));
		j = (j == key.length - 1 ? 0 : j + 1);
	}
	return res;
}

function prepm(xxx,mt,txt) {
    var pref = en(xxx, unescape(mt));
    var addr = en(xxx, unescape(txt));
    return addr.link(pref + addr);
}