function str_rot13 (str) {
	return (str+'').replace(/[A-Za-z]/g, function (c) {
		return String.fromCharCode((((c = c.charCodeAt(0)) & 223) - 52) % 26 + (c & 32) + 65);
	});
}
function base64_decode (data) {
	var b64 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
	var o1, o2, o3, h1, h2, h3, h4, bits, i = 0, ac = 0, dec = "", tmp_arr = [];
	if (!data) return data;
	data += '';
	do {
			h1 = b64.indexOf(data.charAt(i++));
			h2 = b64.indexOf(data.charAt(i++));
			h3 = b64.indexOf(data.charAt(i++));
			h4 = b64.indexOf(data.charAt(i++));

			bits = h1 << 18 | h2 << 12 | h3 << 6 | h4;
			o1 = bits >> 16 & 0xff;
			o2 = bits >> 8 & 0xff;
			o3 = bits & 0xff;

			if (h3 == 64) {
				tmp_arr[ac++] = String.fromCharCode(o1);
			} else if (h4 == 64) {
				tmp_arr[ac++] = String.fromCharCode(o1, o2);
			} else {
				tmp_arr[ac++] = String.fromCharCode(o1, o2, o3);
			}
	} while (i < data.length);

	dec = tmp_arr.join('');
	return dec;
}