Blockchain technology has become of great interest for major multinationals, creating a need to close the gap between the industry and academia. The applications of this peer-to-peer decentralized and immutable data base are countless, yet most of these applications lack a privacy component, which is why only “public blockchains” (mainly cryptocurrencies) actualize into usable applications. At QED-it we are developing a privacy platform on top of any blockchain that uses cryptographic Zero-Knowledge Proofs (ZKPs) in order to prove properties or attributes of private data. These properties are defined as functions computed on the data. Instead of sharing your data on the blockchain, allowing everybody to see it, you can now share the result of a computation and a Zero-Knowledge Proof attesting to the correctness of the computation. We will go over the “Pay to Sudoku” example to understand how to use ZKPs (on the blockchain) and we will overview the main components of zk-SNARKs, one of the better constructions of ZKPs.