Research on Dependability and Security - Dr. Panagiotis Katsaros, Lecturer - Dr. Lefteris Angelis, Assistant Professor - collaboration with other academic staff members

Research on Dependability and Security Dependable Distributed Systems (research started in 2003): Dependable system is a system that meets its expected behavior in all circumstances (performance, availability, reliability and system’s correctness properties like for example safety, atomicity and consistency). Dependability & Security are two interrelated problems (new journal: IEEE Transactions on Dependable and Secure Computing) - a security attack is possible to result in a system’s failure to meet its expected behavior example: recent incident in VODAFONE – Greece, where an insider conversation privacy attack caused an AXE-10 system failure in dispatching SMS messages - correctness property violation like for example an atomicity violation design flaw results in a non secure system

Research on Dependability and Security Areas of interest: quantitative evaluation and trade-offs between dependability attributes (performance, availability, reliability etc) in distributed systems  simulation  stochastic optimization formal methods in the analysis of safety, security and fault tolerance  model checking (SPIN, Colored Petri Nets, AVISPA)  theorem proving (Coq) issues related to access control, information flow control, concurrency control, atomicity and recovery

Research on Dependability and Security Research staff and students: 2 academic staff members 2 PhD students 1 M.Sc. student (thesis) 7 undergraduate students (thesis) Research & Development Projects: EU INTERREG IIIC South programme (MedWet CODDE) ARCHIMIDES II – Greek Ministry of Education (2 projects) Collaboration: Un. of Macedonia, Thessaloniki, Greece Athens Un. of Economics and Business, Athens, Greece CardiSoft, Thessaloniki, Greece

Research on Dependability and Security Recent publications – ongoing research: performance & availability trade-off for different transaction processing alternatives (ACID Sim Tools – ready prototype) ACID properties costs simulation for different Transaction Processing Models and their parameters (protocols for concurrency control, distributed atomic commit, recovery, deadlock handling and replication)

Research on Dependability and Security Recent publications – ongoing research: fault tolerance performance & effectiveness trade-off (replication based or message logging with/without checkpointing) an approach to compare different fault tolerance mechanisms, choose the most effective one and tune its parameters (e.g. checkpoint intervals, number of replicas) such as to achieve the required response times at the lowest possible fault tolerance cost model checking various atomicity properties (in payment transactions) by the use of Colored Petri Nets an approach that can be extended to model checking many other correctness properties in component software models and in models of systems with timing constraints (schedulability analysis)

Research on Dependability and Security Recent publications – ongoing research: new interlocking control algorithm based on the use of the so- called Distributed Signal Boxes, for safety-critical systems (to be published) (correctness properties proved for the Athens underground railway system by the SPIN model checker) new approach for the design of access control in distributed systems, such as to prevent sensitive information leakage formal analysis of smart card security – Public Key Infrastructures (ongoing work) More info: