Add controllers and packages for security keys

resources/scripts/lib/buffer.ts

@@ -0,0 +1,9 @@
+function decodeBuffer(value: string): ArrayBuffer {
+    return Uint8Array.from(window.atob(value), c => c.charCodeAt(0));
+}
+
+function encodeBuffer(value: ArrayBuffer): string {
+    return btoa(String.fromCharCode(...new Uint8Array(value)));
+}
+
+export { decodeBuffer, encodeBuffer };