Editing Zero-knowledge proof (section)

=== Where's Wally ===

One well-known example of a zero-knowledge proof is the "Where's Wally" example. In this example, the prover wants to prove to the verifier that they know where Wally is on a page in a ''[[Where's Wally?]]'' book, without revealing his location to the verifier.<ref name=Murtagh>{{cite news
  | last         = Murtagh
  | first        = Jack  
  | date         =  July 1, 2023
  | title        = Where's Wally? How to Mathematically Prove You Found Him without Revealing Where He Is
  | url          = https://www.scientificamerican.com/article/wheres-waldo-how-to-prove-you-found-him-without-revealing-where-he-is/
  | work         = [[Scientific American]]
  | access-date  = 2023-10-02
}}</ref>

The prover starts by taking a large black board with a small hole in it, the size of Wally. The board is twice the size of the book in both directions, so the verifier cannot see where on the page the prover is placing it. The prover then places the board over the page so that Wally is in the hole.<ref name=Murtagh/>

The verifier can now look through the hole and see Wally, but cannot see any other part of the page. Therefore, the prover has proven to the verifier that they know where Wally is, without revealing any other information about his location.<ref name=Murtagh/>

This example is not a perfect zero-knowledge proof, because the prover does reveal some information about Wally's location, such as his body position. However, it is a decent illustration of the basic concept of a zero-knowledge proof.