How to create a "safe box enter right password" to unlock levels?

At the end of each level for my game, I want players to open a safe using the right passcode (this passcode is a static 6-digit string) to earn rewards and proceed to the next level. This is the experience I have in mind:

What is the most efficient way to do this and how do I make it so that the "*******" appear as I'm typing out the passcode. Thank you! Sorry if this question had been answered before, I couldn't find anything relevant.

Here you go:

dropbox.com/s/wpc08rq21lc8qa7/PasswordBox.c3p

I used Button object for keys as it's easier, but of course you can use sprites.

Here you go:

https://www.dropbox.com/s/wpc08rq21lc8qa7/PasswordBox.c3p?dl=0

I used Button object for keys as it's easier, but of course you can use sprites.

Thank you so much! Your method is so much easier than what I had setup originally.