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Secure Communications Processor (SCOMP)

Secure Communications Processor (SCOMP) was a system, including hardware and a security kernel, developed by Honeywell Information System's Federal Systems Division in order to implement the Multics multilevel security requirements and as a follow-on to the Air Force-Honeywell Multics enhancements known as Project Guardian. SCOMP was a project of Honeywell supported by the Naval Electronics System Command. Parallel efforts in provably secure computer systems were done at UCLA, MITRE, and Ford Aerospace with KSOS and at SRI with PSOS.(1)

Honeywell originally intended to develop a security kernel and a software emulator that would run UNIX in a virtual environment. But the impact on system performance and, especially, the concerns about operating-system security were sufficient to warrant developing a new operating system for the SCOMP minicomputer architecture. As a result, the SCOMP security kernel controlled access to system resources, requiring that an application submit a hardware descriptor to the security kernel in order to request access to secured hardware resources. The kernel then permitted or denied that application access to hardware depending upon established permissions for each process. Honeywell advertised that its regular commercial-grade DPS/6 16-bit minicomputer could be transformed into a secure SCOMP machine by swapping out the regular CPU for a secure CPU unit and adding a security-protection module (SPM).(2)(3)

After being in TCSEC evaluation process for two years, SCOMP received TCSEC A1 certification in 1984. The full-blown SCOMP operating system, "Scomp Trusted Operating Program" or STOP, was also awarded A1 the following year.(4) It evolved into subsequent secure systems, such as XTS-200, XTS-400.(5)(6)

Honeywell SCOMP architecture from Fraim, "Scomp: A Solution to the Multilevel Security Problem," Computer (July 1983), 28.

Notes

1 : See also CBI project interviews with Earl Boebert and Richard Kain.

2 : Lester J. Fraim, "Scomp: A Solution to the Multilevel Security Problem," Computer (July 1983), 26-34.

3 : Trent Jaeger, Operating System Security (Morgan & Claypool, 2008), 77-80.

4 : Steven J. Padilla and Terry Benzel, Secure Communications Processor (SCOMP): STOP Release 2.1 (23 September 1985) available at DTIC.

5 : BAE Systems Information Technology, LLC, Common Criteria Evaluation and Validation Report Scheme. XTS-44/STOP 6.1.E. CCEVS-VR-05-0094, Gaithersburg, MD (National Institute of Standards and Technology, March 1, 2005), 5. (Login required)

6 : Lester J. Fraim, "Scomp: A Solution to the Multilevel Security Problem," IEEE Computer (July 1983): 26-34 on 26-27. DOI