I need to create a very simple program, that should run on raspberry pi without network connection. The program should first show one full-screen bitmap ("insert disk"), and after receiving somehow an external signal (disk inserted), another bitmap which would ask to input password. After inputting the password (each pushed button shows an asterisk *) the application should show yet another bitmap, which would inform whether the password was correct or not.
So in principle I would like to create something that looks like password screen in any Hollywood movie!
Raspberry should boot directly to the application.
I was expecting that this would be easy to do (and it would be if we could use Windows and Visual Studio), but I haven't yet found a simple tool to create this for pi. Booting Raspberry into browser with kiosk mode and creating HTML application seems like an overkill.
Although a browser in kiosk mode might look that a sledgehammer to crack a nut, I think you might find this nut harder than it looks.
It wouldn't be difficult to write a simple app in Java, or Python, or perhaps even C using GTK, that carries out the actions you want. You could have the app loaded when X starts, as an alternative to a desktop and Window manager. You could even do away with X altogether, and write some code that interacts directly with the video framebuffer and the keyboard hardware. Or, heck, go the whole hog, and have your code substitute for the operating system kernel :)
I would guess that even the simplest of these approaches involves more work than hacking something up using a HTML and JavaScript in a browser.