ACF2 (Access Control Facility 2) is a

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discretionary access control In computer security, discretionary access control (DAC) is a type of access control defined by the Trusted Computer System Evaluation Criteria (TCSEC) as a means of restricting access to objects based on the identity of subjects and/or groups to ...

software security system developed for the MVS (z/OS today), VSE (z/VSE today) and VM (z/VM today) IBM mainframe

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by SKK, Inc. Barry Schrager, Eberhard Klemens, and Scott Krueger combined to develop ACF2 at London Life Insurance in

London, Ontario London is a city in southwestern Ontario, Canada, along the Quebec City–Windsor Corridor. The city had a population of 422,324 according to the 2021 Canadian census. London is at the confluence of the Thames River (Ontario), Thames River and N ...

in 1978. The "2" was added to the ACF2 name by Cambridge Systems (who had the North American marketing rights for the product) to differentiate it from the prototype, which was developed by Schrager and Klemens at the

University of Illinois The University of Illinois Urbana-Champaign (UIUC, U of I, Illinois, or University of Illinois) is a public university, public land-grant university, land-grant research university in the Champaign–Urbana metropolitan area, Illinois, United ...

—the prototype name was ACF. The "2" also helped to distinguish the product from

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's ACF/VTAM. ACF2 was developed in response to IBM's RACF product (developed in 1976), which was IBM's answer to the 1974 SHAREbr>Security and Data Management project's requirement whitepaper
ACF2's design was guided by these requirements, taking a resource-rule oriented approach. Unique to ACF2 were the concepts of "Protection by Default" and resource pattern masking. As a result of the competitive tension between RACF and ACF2, IBM matured the SAF (Security Access Facility) interface in MVS (now z/OS), which allowed any security product to process operating system ("OS"), third-party software and application security calls, enabling the mainframe to secure all facets of mainframe operations. SKK and ACF2 were sold to UCCEL Corporation in 1986, which in turn was purchased by Computer Associates International, Inc. in 1987. Broadcom Inc. now (2019) markets ACF2 as CA ACF2.

References

Operating system security Computer access control frameworks CA Technologies IBM mainframe software {{operating-system-stub