Private information retrieval

So imagine you have a lot of toys, but you don't want your friend to know which ones you have. But your friend is curious and wants to know if you have a particular toy.

Private Information Retrieval is like a game that lets your friend ask you yes or no questions about your toys, but in a way that you don't reveal which toys you actually have. For example, instead of asking "Do you have the blue car?" which would reveal that you have a blue car if you said "yes", your friend can ask a more complicated question like "Do you have more blue toys than red toys?"

This way you can answer truthfully without revealing exactly what toys you have, and your friend can find the information they want without invading your privacy. It's like a secret code that helps your friend find what they want without giving anything away.