One-time pad

Okay kiddo, so let me tell you about a way to keep messages secret called the "one-time pad."

Imagine you want to write down a secret message to your friend, but you don't want anyone else to be able to read it. Now, you could just use a regular code like in a secret spy book, but if someone figures out the code, they can read your message too!

The one-time pad is special because it's super-duper hard to crack! Here's how it works:

First, you and your friend each get a super long list of random letters, numbers, and symbols. It's like a secret codebook that only you two have.

When you want to send a secret message, you take a letter from your message and find the matching letter in your secret codebook. Then, you write down the letter that's across from it on your friend's codebook!

For example, if you want to write "CAT", you might find the letter "C" on your own codebook and then look across to see that you need to write "M" on your friend's codebook. You do this for every letter in your message.

Now, without your codebooks, nobody can decode your message because they don't know which letters match which! And the best part is that you only use each letter pairing once - like a disposable code. This makes it nearly impossible for anyone to break the code because they can't find any patterns or repeat combinations.

That's why it's called a "one-time pad" - you only use each page of your codebook once, and then you throw it away and use a new one for the next message.

So now you know about the one-time pad - a super safe way to send secret messages to your friends!