Lecture depicts the project OPIS that has been implemented by the Ministry of Interior - Information System for identifying individuals whose goal is to create a single, data-consistent source of basic identifiers of individuals who come into contact with the public administration and are registered in the register of individuals. The basic identifiers ensure uniqueness of individuals in information systems and at the same time increase the privacy of individuals kept in different information systems in public administration and enable effective communication between these systems without the risk of leakage of data from various databases and information systems.