A confidentiality level assigns information to a protection class and determines who may access it and which safeguards apply. Typical tiers include Public, Internal, Confidential, and Strictly Confidential. In an ISMS, confidentiality levels form the basis for information classification per ISO 27001 Annex A.5.12. Each level carries specific handling instructions for storage, transmission, and destruction. Clear level definitions help all employees handle information correctly in day-to-day work.