NSA has interesting site for kids’ games in area of cryptology. It says:
Welcome to the NSA/CSS Kids’ page.
We’re the CryptoKids and we love cryptology.
What’s cryptology? Cryptology is making and breaking codes. It’s so cool. We make codes so we can send secret messages to our friends. And we try to figure out what other people are writing about by breaking their codes. It’s a lot of fun.
Visit it here.