Files containing surveillance material created by the Hungarian state security organs were included in different categories according to the subject of surveillance:
Group File – It was opened when a confidential investigation of a group of persons began. For conspiration reasons, the group was given a code name.
Surveillance File – It was opened for a person whose activities and behaviour were continuously monitored by the state security because the person was regarded as “a hostile element posing a threat to the society”.

Personal File – When a confidential investigation of a person began, a Personal File was opened. For conspiration reasons, “highly dangerous” persons were given aliases in the file.
Facility File – Facility (or Line) Files were opened for facilities which were significant from state security perspectives (factories, schools, authorities, etc.) Such facilities were the diplomatic missions, the major specialized areas and significant facilities of the army as well as scientific and ideological institutions. Churches and religious communities (sects) also belonged here. Facility Files contained data related to persons in the records classified according to categories established by the state security (e.g. aristocrats, gendarmerie, etc.).
Surveillance material can be found in the Work Files, which contained the reports created by the collaborators: hand-written reports by collaborators (agents, residents, informants, secret staff, etc.) using aliases were included in the Work Files in a chronological order. If the report was regarded as valuable, a typed version was also added. At the end of the report the case officer wrote an assessment of the report from state security perspective and listed the new tasks assigned to the collaborator.