You can check out the source for the demo at https://github.com/xtermjs/xtermjs.org/blob/master/js/demo.j..., I've actually started hacking up a more general mechanism for doing this since I've done it a few times but it's not OSS yet.

If you don't need to rely on ccrypt and just want to emulate teh experience of using it, you could have an on rails experience by forking the demo file and adapting the commands part.