Soumik Mondal defended his dissertation

Soumik Mondal defended his doctoral thesis for the degree of PhD in Information Security at the Faculty of Computer Science and Media Technology, NTNU February 24.

The thesis was titled "Continuous User Authentication and Identification: Combination of Security and Forensics", and examines how to prevent unauthorized use of computers by using continuous authentication.

For most computer systems, once the user’s identity is verified at login, the system resources are available to that user until he/she locks the session. In fact, the system resources are available to any user during that period. This can lead to session hijacking, in which an attacker targets an open session, e.g. when the genuine user gets a cup of coffee, or leaves to talk to a colleague.

To avoid unauthorized use of a computer and its resources, a continuous check of the user’s identity is important. Continuous Authentication has built around the biometrics supplied by the user’s physical or behavioural characteristics and continuously checks the identity of the user throughout the session.

But once it is discovered that it is not the genuine user that is using the computer, it is important to be able to identify who the imposter is. Mondal is the first to look at the issue with identifying the imposter in this manner. He has contributed a dynamic model that is able to make a decision on the genuineness of the user after each single action performed by the current user, as well as an identification technique that has achieved good results.

Mondal’s main supervisor has been Professor Patrick Bours, NTNU and co-supervisor has been Professor Christophe Rosenberger, ENSICAEN, France.

Assessment committee:

  • First External opponent: Professor Issa Traore. University of Victoria, ECE Department, ISOT Lab, Canada.
  • Second External opponent: Assistant Professor Luuk Spreeuwers. University of Twente, Faculty of EEMCS, The Netherlands.
  • Internal opponent: Associate Professor Basel Katt. AIMT, NTNU. Substitute for Basel Katt on 24 February was Prof. Slobodan Petrovic, AIMT, NTNU.
  • Associate Professor Sule Yildirim-Yayilgan, AIMT/NISlab, NTNU was the administrator for the assessment committee.

Dean Nils Kalstad Svendsen, AIMT conducted the public defense.


From left: Issa Traore, Luuk Spreeuwers, Sule Yildirim-Yayilgan, Soumik Mondal, Slobodan Petrovic, Nils Kalstad Svendsen, Patrick Bours.