Local Area Networks (LANs) in Aircraft - FTP Directory Listing - FAA

level). This pairing potentially provides a framework for considering FAA and the CC processes
and concepts in an integrated manner. Specifically, it is conceivable that the modest FAA
confidentiality requirements (if any) roughly equate to the DoD public (i.e., basic)
confidentiality level, such that the DO-178B software levels can be mapped into the public
variant of the three different MAC levels to identify IA (i.e., security) requirements for FAA
systems. Of course, since DoDI 8500.2 is a DoD document, this association is in terms of DoD
processes, and not FAA processes. However, it does provide a possible intersection that may be
relevant for increased synergy between the DoD and FAA.
Therefore, DoDI 8500.2 may provide a starting point for potentially integrating airborne network
safety and security concepts into a common federal system by leveraging established DoD
processes that comply with federal law. Nevertheless, to pursue this, the FAA needs to study
and verify whether the three MAC levels identified by DoDI 8500.2 provide adequate
granularity for the NAS and airborne system requirements. If they do, then the FAA could
potentially directly leverage current DoD processes, if appropriate, perhaps creating a
government-wide integrated safety and security engineering system.
Regardless, this study concludes that this issue needs further study to be useful. Consequently,
at this time, it does not provide the assurances needed to underlie the exemplar airborne network
architecture. Therefore, this study will tentatively relate safety and security issues in terms of
the relative assurances provided by their respective certification processes.
The CC has provided seven predefined security assurance packages, on a rising scale of
assurance, which are known as evaluation assurance levels (EAL). EALs provide groupings of
assurance components that are intended to be generally applicable. The seven EALs are as
follows:
• EAL 1—Functionally Tested
• EAL 2—Structurally Tested
• EAL 3—Methodically Tested and Checked
• EAL 4—Methodically Designed, Tested, and Reviewed
• EAL 5—Semiformally Designed and Tested
• EAL 6—Semiformally Verified Design and Tested
• EAL 7—Formally Verified Design and Tested
EAL 1, therefore, is the entry level classification of the system. EAL 1 through EAL 4
(inclusive) are expected to be generic commercial products. EAL 5 through EAL 7 (inclusive)
are considered to be high-assurance products.
Carol Taylor, Jim Alves-Foss, and Bob Rinker of the University of Idaho have studied the issue
of dual software certification [93] for CC and DO-178B. Figure 28 is copied from their study
and shows a high-level gap analysis between the CC classes and the DO-178B processes. Their
study provided a fairly detailed analysis of the differences. Their study suggested that security
functionality certified at EAL 5 can be directly compared with DO-178B Level A.
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