# Security Assessment of Agriculture IoT (AIoT) Applications
## 2 Materials and Methods
### Process Step: SuC Identification
#### 2.4.1 SuC Identification Key Questions  
System relevant questions:  
1. What is the SuC? 2. Based on the SuC definition, what are the borders of the system? 3. Which parts of the system are not part of the SuC? Asset relevant questions:  
1. What are the assets of the system? 2. Which assets are not part of the analysis? 3. Which assets are outside of the SuC? Interface relevant questions:
2. Which data communication interfaces reach from the outside into the SuC? 3. Which protocols are used by the interfaces? When the SuC is carefully defined and documented, an imported step is done to know the assets, which must be protected against cybersecurity attacks. In the IACS domain, IEC 62264 defines an edition of functional hierarchies of the industrial automation process (IAP) [9], as shown in Figure 3.  
The \"Sensing and Actuation\" segment is located at the bottom of the pyramid, with the sensors and the actuators (IAP: Level 1). On top of the pyramid is the \"Business Planning and Logistics\" segment (IAP: Level 4). Between these segments, both the \"Monitoring, Supervision and Control\" segment and the \"Manufacturing Operations and Controls\" segments are arranged (IAP: Level 3 and Level 2). In most cases, Level 0, Level 1, and Level 2 are found at a single geographical location, generally in a company building. Level 3 and Level 4 could be located far away from the building, possibly anywhere worldwide. The top levels can operate by using cloud-based services and can be partially outsourced to third-party companies. These decentralized system architectures are becoming more and more general for both large and medium-sized companies. In AFarCloud, a comparable system architecture for agriculture applications was defined and developed as shown in Figure 1. It is divided into four main-segments. On the bottom, in the \"Field\" segment, there are the sensors and the actuators for the livestock and crop process activities. On the top \"Farm Management\" segment, functions, such as mission management and configuration, are provided. Also, the data repositories are installed in the top segment level by using cloud-based services. The \"Semantic Middleware\" segment provides services to collect and distribute data and to perform decision finding by processing actual and historical data. In this segment, the CSM services are installed to support the overall system with security processes. The \"Farm\" segment provides the OT functionalities for data collecting and distributing, and acts as the fog or edge computing layer. In Figure 1, all communication interfaces established between the segments are illustrated. While, in the field segment, numerous different communication protocols are in use, adapted for a special use and application, the higher segments are only supported by some selected communication paths and protocols to improve the data and cybersecurity. The yellow key and lock symbols give a rough overview of implemented cybersecurity measures. The following overview lists all assets of the system architecture. Only a short excerpt of the available hardware and software and the communication protocols in use are given. In a real cybersecurity assessment, the system documentation is performed in more detail. Each detail of interest is important to find the appropriate security protection level and to identify potential security vulnerabilities. Field segment:  
Hardware/software assets:  
Figure 3: Industrial production functional hierarchies, according to IEC 62264. * Livestock collar sensors
* Temperature, humidity sensors (soil and air)
* Air quality sensors
* Light spectral sensors
* Cameras
* Vehicles
* Drones
* In-vehicle data display monitors
* Outdoor data display monitors
* Cellular phones
* Data gateways  
Communication protocols:  
* Cellular phone protocol LTE and 4G
* Bluetooth
* LoRaWAN
* WLAN
* Sigfox  
The drones link directly via cellular communication to the Data Distribution Service (DDS) manner in the semantic middleware using the DDS protocol.