Oblivious transfer

Okay kiddo, so imagine you have two candy jars and your friend has two candies that you really want. But your friend only wants to give you one candy and keep the other one. So you want to choose which candy you get, but you don't want your friend to know which candy you picked.

That's kind of like what oblivious transfer is! It's a way for two people to share information without either one of them knowing what the other person chose.

Instead of candy jars and candies, though, it might be something like secret codes or passwords. Let's say you and your friend want to share passwords for your secret clubhouses. Your friend has two passwords, but they only want to share one with you. So you use oblivious transfer to choose which password you get without your friend knowing.

The way it works is a bit like a magic trick. You and your friend each have a piece of paper with something written on it (maybe a password or code). You both put your pieces of paper in separate envelopes and seal them up. Then you shuffle the envelopes so you don't know which one has your friend's password in it.

Next, you and your friend take turns doing some magic tricks. You both do the same tricks, but you don't know which envelope the other person is working with. The trick is designed so that at the end, you each end up with one envelope, but neither one of you knows which one has the correct password in it.

Finally, you and your friend reveal which envelope you each picked, and you open them up to see which password is inside. Since you both did the same magic tricks, each of you had an equal chance of ending up with the correct password.

So, that's basically what oblivious transfer is! It's a way for two people to share information without either one of them knowing what the other person chose. It's like a magic trick that keeps secrets safe.