The Administration system for the state information system (RIHA) (Estonian: Riigi infosüsteemi haldussüsteem – RIHA) of Estonia is the Estonian catalogue of public sector information systems. It serves as the national registry of systems, components, services, data models, semantic assets. From a legal point of view, RIHA is a set of principles as well as a major state register. It is regulated by the Public Information Act and a special regulation. The use of RIHA is mandatory for state agencies. Technically, RIHA is a secure web-based database and software application.