Resource Access Control Facility

RACF, 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.

It fulfills the main features:

• Identification and verification of a user via user id and password check (authentication)
• Identification, classification and protection of system resources
• Maintenance of access rights to protected resources (authorization)
• Control the means of access to protected resources
• Logging of accesses to a protected system and protected resources (auditing)

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 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.