# SPD-Safe: Secure Administration of Railway Intelligent Transportation Systems
## 5 SPD-Safe Demonstration
### Indoor Setting--Cyber-Security  
The demonstration setting includes a carriage/shelter inspecting application, which is equipped with a surveillance system and WSNs. Those components are sensitive to  
Figure 4: The smart railway use case architecture. network layer threats, like jamming and blackhole attacks. The deployed network is depicted in Figure 5, where these devices are deployed in a shelter [28]:  
* At the entrance, the smart camera inspects for physical intrusion;
* Two WSNs are deployed in the shelter. WSN\({}_{1-1}\) (green color) monitors light and temperature, and WSN\({}_{1-2}\) (red color) senses temperature. WSN\({}_{1-1}\) and WSN\({}_{1-2}\) utilize different hardware to enhance diversity and ensure redundancy for the monitored factors;
* A gateway interconnects the rest of the components with the C&C. WSN\({}_{1-1}\) consists of eight Memsic Iris sensor nodes (16 MHz Atmel ATMega 1281 processor, 8 KB RAM, Contiki OS). The devices are battery powered and measure light and temperature. Furthermore, the smart camera is controlled by the node at the carriage's entrance. WSN\({}_{1-2}\) is installed for redundancy and is comprised of Zolertia Z1 sensor nodes (16 MHz MSP430 processor, 8 KB RAM, and Contiki OS) that collect temperature data. The two WSNs are monitored by two relevant simple agents (SA\({}_{1-1}\) and SA\({}_{1-2}\) respectively). Every device executes the PEP module of the PBAC framework. The devices also exchange data with the gateway, which runs the access policies for PBAC, and communicates with an MA which administrates the whole network. The devices gather environmental information and send data to the relevant base station (laptop with WiFi connectivity). This component integrates and processes the received information. It also runs an application with which the user accesses and manages the overall testbed. The different components are evaluated by the corresponding agents, who also estimate the aggregate SPD value of the whole system. The agents inspect their underlying domain, managing it based on an SPD-aware reasoning operation. Furthermore, the system is re-configurable at runtime according to the SPD protection and performance goals defined in the activated policy. Affected agents configure their subsystem's settings to raise the SPD value when attacks are performed and then return to normal when the attacks are over (to save resources). Regarding the adaptation capabilities integrated within the proof-of-concept, the cryptographic service provides three communication states: Plain-text, authenticated, as well as authenticated encryption. Additionally, the trust scheme  
Figure 5: The internal wireless sensor network (WSN) for the carriage setting. supports two trust evaluation states: Direct trust only, as well as a combination of direct and indirect trust. The system begins with a moderate SPD configuration to conserve resources (i.e., authenticated communication and direct trust). If SPD-Safe observes malicious activity, it informs the system entities to raise their protection level. The relevant response actions are specified in a security policy (applicable to the specific device type), such as applying authenticated and encrypted communication with combined direct and indirect trust information. The SPD value and status of each system component is then altered as a response to the launched attacks, so as to achieve a sufficient level of protection. The WSNs comply with the current policies, becoming stricter to misbehavior and isolating the compromised nodes. The main protection mechanism against cyber-attacks (i.e., blackhole or link-spoofing) is provided by SecRoute, while the smart camera enhances physical protection. In the same way, the system returns to the previous (initial) state when the triggering conditions are over. For WSN\({}_{1\text{-}1}\), we emulate scenarios where: (i) A node is malfunctioning due to low battery, and (ii) a compromised node launches a badmouth attack.