Oh, I knew I forgot something in the readme.
As a shell script, it does not display any visual indication that you are typing anything. This is a security feature, not a bug. It is to prevent anyone who is looking over your shoulder from seeing how long your password is. It's an old UNIX-ism, and always confusing to people who are used to e.g. password forms on Web browsers which display bullet points instead of letters.
So, even though it doesn't look like you're typing anything in, you are typing the password in. Just type it in and hit enter. It should work.