This document sets forth guidance for life-cycle management of public/private (i.e., asymmetric) keys that are used to secure interactions among systems.

The scope of this guidance is not intended to include:

• Any off-board, ground-based systems, including those with which aircraft systems and operator-controlled PEDs may communicate. Ground-based systems do not have the unique constraints and challenges associated with global, mobile aircraft systems; therefore, they are expected to reference guidance in ATA Spec 42 as applicable to typical IT environments.

• Passenger-owned devices, which are beyond the control of the aircraft operator.

• Operator-controlled PEDs that are treated like passenger-owned devices.

This document is meant to be a companion to Air Transport Association (ATA) Spec 42, which is the work product of the ATA Digital Security Working Group (DSWG). ATA Spec 42 specifies a digital identity management framework and standard digital certificate profiles recommended for use across the air transport industry, as well as standard policies governing the issuance and use of these certificates and the levels of assurance that may be conveyed in a digital identity. This document specifically addresses ATA Spec 42 in the context of actual aircraft deployment by providing guidance to aircraft manufacturers, equipment suppliers, and operators on topics including:

The guidance in this document is focused on the medium identity assurance level described in ATA Spec 42. Chapters 3-2-1 and 3-6-2(1) of ATA Spec 42 define the concept of "trust" provided by various levels of identity assurance, based on factors such as the quality of the identity-proofing process and various technological, personnel, and procedural controls, as outlined in a Certificate Policy. The medium assurance level provides moderate trust in the binding of the public key certificate to the subject, and controls on the private key may be moderate or strong depending on whether software or hardware implementations (respectively) are employed. As suggested in Chapter 3-4 of ATA Spec 42, the medium assurance level is expected to apply broadly to air transportation applications; however, selection of the appropriate assurance level must be based on a risk assessment, system requirements, and operational constraints. For cases where low credential assurance is determined to be acceptable, the guidance in this document may be tailored to accommodate the lower level.