Lattice-based cryptography

Imagine you have a big room with lots of chairs in it. You want to keep someone out of the room and make sure they don't steal anything inside. You decide to put a big wall up in front of the door so no one can get in. However, the person trying to get in can just climb over the wall or break through it.

So you come up with a new idea. Instead of a wall, you stretch a really big net across the doorway. This net has really tiny holes that are too small for someone to climb through or break. This stops the person from getting in and stealing anything from the room.

Lattice-based cryptography is like that big net. It creates a really complicated mathematical puzzle that is too hard for someone to solve and break into. This makes sure that no one can see or change any of the information that you want to keep safe. Just like how the tiny holes in the net stop someone from getting in, the complicated puzzle in lattice-based cryptography stops someone from breaking in and stealing the information.