5.2 AE and CSE access security services within the SE

In this scenario, both the AE and the CSE reside within a Node as depicted in figure 5.2-1. The AE (or CSE) is split into a secure and a non secure part whereas the security relevant part AE_sec (respectively CSE_sec) resides within the SE and the corresponding non security relevant part AE_ (respectively CSE_) resides within the application space of the node. The AE_ (respectively CSE_) accesses AE_sec (respectively CSE_sec) via the Maa reference point. In addition the AE and the CSE can access security services offered by the SE via the Mcs reference point.

Figure 5.2-1: Secure Environment architecture of a Field Domain Node

The SE is integrated into the node as follows:

• Logically: the SE offers its sensitive functions f(x)_sec and its security resources res_sec to AEs and CSEs residing within the field domain node via the Mcs reference point. In addition the AE_sec or CSE_sec may offer corresponding services to the AE_ or CSE_ via a proprietary Maa reference point. AE_sec may also access the CSE via the Mca reference point.
• Physically: in case the SE is a dedicated hardware component, it has to be integrated into the node physically including low level drivers that enable logical access to the SE. The physical connection is superfluous in case the SE is implemented in software.