International Journal of Critical Computer-Based Systems (3 papers in press)

Regular Issues

• Iterative integration of TTEthernet network flows  
  by Sofiene Beji, Sardaouna Hamadou, John Mullins, Abdelouahed Gherbi 
  Abstract: TTEthernet has been proposed as an improvement of the Ethernet network protocol to ensure communication of critical systems. Some of these systems, such as avionics systems, are complex and evolving ones. Therefore, they are designed iteratively by integrating in each iteration some components of the system. Adding new functionalities may induce substantial additional costs of reconfiguration of the system in order to meet the real-time requirements. Based on the constraint programming techniques, we develop in this paper a cost optimization approach that meets the TTEthernet specification and validates the latencies requirements in an accurate way. We illustrate our approach on a case study with the MiniZinc tool (Nethercote et al. , 2007).
  Keywords: TTEthernet; Iterative Integration; Scheduling; Real-Time Systems.
  
  
• A Challenge based Countermeasure against the Spoofed PS-Poll based DoS Attack in IEEE 802.11 Networks  
  by Souilah Hocine, Baadache Abderrahmane, Bouallouche-Medjkoune Louiza 
  Abstract: 802.11 network is an emerging wireless broadband technology used to connect client stations to the network via an access point (AP). This network is particularly vulnerable to DoS (Denial of Service) attacks targeting the network availability. In this paper, we focus on the spoofed PS-Poll based DoS attack in 802.11 PSM (Power Save Mode), where the attacker spoofs the polling frame on behalf of the client in order to destruct data buffered at the AP, that are expected to be delivered to asleep client. To cope with this attack, we rely on the prime factorization to authenticate PS-Poll frame needed to retrieve buffered data. The countermeasure we propose, called APSP (Authenticated Power Save Poll), is both detective and preventive one with low communication, computing and storage overheads. It can be integrated in 802.11 standard through firmware upgrade without any required additional hardware. In order to prove the efficiency of the proposed countermeasure and evaluate its performance, extensive experiments are carried out. Simulation results show that the spoofed PS-Poll based DoS attack is successfully prevented and detected by APSP compared to the basic 802.11 PSM.
  Keywords: IEEE 802.11; Power Save Mode; PS-Poll; DoS attack; Prime factorization.
  
  
• Design, Implementation, and Assessment of a Usable Multi-Biometric Continuous Authentication System  
  by Enrico Schiavone, Andrea Ceccarelli, Ariadne Carvalho, Andrea Bondavalli 
  Abstract: Authentication mechanisms typically verify the user identity only at login, or with tedious explicit authentication requests that improve security at the expense of usability. However, especially for critical systems, workstations have to be tightly and continuously secured in order to prevent unauthorized interventions. Recent researches envisage multi-biometric systems for continuous authentication, where biometric traits are acquired transparently to the user and authentication is provided without requiring explicit actions. In this work we propose a multi-biometric authentication system that continuously and transparently verifies the user identity through face, fingerprint and keystroke recognition. This paper presents the design, prototype implementation and assessment of our system. We evaluate the system usability and its trade-off with security in an experiment involving 60 users. Our findings show that security enhancements are provided and users i) perform the actions without additional effort, ii) largely accept the authentication system, which only requires minimal training.
  Keywords: continuous authentication; biometrics; security; usability; identity verification; multi-biometric; transparent; face; fingerprint; keystroke; prototype; assessment; design; implementation;.