Crypto AG is a company that makes machines that can help people keep their messages secret. It's like a secret code that only you and the person you're talking to can understand.
So imagine you have two people who want to talk to each other, but they don't want anyone else to know what they're saying. They can use a machine made by Crypto AG to encrypt their messages. This means that the message will be jumbled up and unreadable to anyone who doesn't have the special key to unscramble it.
Now let's say another person comes along and tries to intercept their message. But even if they can see the jumbled up message, they won't be able to understand it because they don't have the key to unscramble it.
This is like a game of hide-and-seek. The people who are trying to keep their messages secret are hiding their message in a secret code that nobody else knows. And even if someone finds their hiding spot, they won't know how to read the message without the key.
Crypto AG became famous because they sold these machines to many different countries around the world, including some that were enemies of each other. This meant that some countries were able to spy on other countries without them even knowing it.
So in summary, Crypto AG makes machines that can help people keep their messages secret by encrypting them. Only the people with the special key can unscramble the message and understand what it says. This helps keep messages secret from people who might want to spy on them.