In this presentation, we will introduce the basic concepts of Zero-Knowledge proofs. We will see how the privacy of personal data can be achieved using Zero-Knowledge proof. We will refer to two research that we conducted within the 3327 team, which deal with the privacy and anonymity of users. One of them is MACI (Minimal Anti-Collusion Infrastructure), which is a project developed by Ethereum that should enable a voting system that is completely resistant to collusion. As this has not been achieved at the moment, our research has shown how, using Zero-Knowledge proof, the privacy and anonymity of each voter can be completely preserved.