Designated verifier signature

Okay kiddo, so imagine you have a secret message that you want to send to your friend, but you only want your friend to be able to read it. To make sure your friend knows the message came from you and nobody else changed it, you can use something called a designated verifier signature.

It's like giving your friend a special stamp or mark that only they can understand. You put the stamp on the message to show it's from you, but your friend has to use a special key to unlock and read the message. This means nobody else can read it, even if they try really hard.

It's kind of like a secret code between you and your friend, and nobody else can break the code because they don't have the special key. So now you can send secret messages to your friend and know that it's safe from prying eyes! Cool, huh?