Private Set Intersection (PSI) is a cryptographic protocol that allows two (or more) parties, each holding a set of items, to compute the intersection of their sets without revealing any items outside the intersection. That is, each party learns only which items they have in common, and nothing else about the other’s data. For example, two companies could collaborate to find out which customers they share without disclosing any customers that are unique to one company. PSI is a special case of secure multi-party computation focusing on set overlap; it has applications in private contact discovery, privacy-preserving data mining,..In this thesis, we study PSI improvements with fully holomorphic encryption.