RACF, [usually pronounced Rack-Eff] short for Resource Access Control Facility, is an IBM software product. It is a security system that provides access control and auditing functionality for the z/OS and z/VM operating systems. RACF was introduced in 1976.
Its main features are:
RACF establishes security policies rather than just permission records. It can set permissions for file patterns — that is, set the permissions even for files that do not yet exist. Those permissions are then used for the file (or other object) created at a later time .
RACF has continuously evolved to support such modern security features as digital certificates/public key infrastructure services, LDAP interfaces, and case sensitive IDs/passwords. The latter is a reluctant concession to promote interoperability with other systems, such as Unix and Linux. The underlying zSeries (now z Systems) hardware works closely with RACF. For example, digital certificates are protected within tamper-proof cryptographic processors. Major mainframe subsystems, especially DB2 Version 8, use RACF to provide multi-level security (MLS).
Its primary competitors have been ACF2 and TopSecret, both now produced by CA, Inc.