Michael Bamiloshin
PhD Programme: Computer Science and Mathematics of Security
Research group: CRISES – Data security and privacy
Supervisor: Oriol Farràs Ventura
Bio
Michael Bamiloshin studied in the University of Ilorin, Nigeria, where he obtained a Bachelor of Science degree in Mathematics. Following this, he proceeded to the University of L'Aquila, Italy, and then the University of Silesia, Poland, obtaining a double Masters degree in Mathematical Engineering from both schools. His master's thesis was titled “Secret Sharing Schemes and Hierarchical Access Structures”. His work on this topic piqued his interest in cryptography, secret sharing and secure Multiparty Computation (MPC) and eventually led to him joining the CRISES Research Group in the URV, where he is currently working as a PhD student. Apart from his research work, he is also assisting in teaching the Cryptography and Information Security course in the Department of Computer Engineering and Mathematics.
Project: Common information techniques for the study of matroid representation and secret sharing schemes
The characterization of representable matroids is a longstanding open problem. This problem is connected to the characterization of access structures that admit ideal secret sharing schemes. In these schemes, the size of each share is equal to the size of the secret, which is an optimal situation. In this thesis, we develop new techinques to check representability properties that are based on different results of information theory such as the common information property and the Ahswelde-Körner lemma. With these techniques, we give a complete characterization of matroids on 8 points that admit folded linear (i.e., multilinear) representations, finding the smallest matroids that are not linearly representable but admit folded linear representations. Combining these new techniques based on information theory with the Euclidean intersection property and other matroid intersection properties, we move further to 9-point matroids, finding new families of non-representable matroids that are Ingleton-compliant. We give lower bounds on the information ratio of secret sharing schemes for the ports of all matroids on 8 points and show a separation result for non-Ingleton- compliant sparse-paving matroids. We show that ports of sparse-paving matroids admit schemes with sub-exponential share size. We also present exponential lower bounds for the information ratio of linear secret sharing schemes for almost all matroids.
Open Access publications
- Bamiloshin, M., Ben-Efraim, A., Farràs, O., Padró, C.: Common information, matroid representation, and secret sharing for matroid ports. Des. Codes Cryptogr. 89, 143-166 (2021). View full-text
- PHD THESIS: Common information techniques for the study of matroid representation and secret sharing schemes
International secondment
- Renyi Institute of Technology, Budapest, Hungary, 3 months, 2020.
Outreach activities
- European Researchers' Night 2019: "Coneix el teu doble científic!".
Awards & Prizes
- Ferran Sunyer i Balaguer Scholarship, awarded by the Fundació Ferran Sunyer i Balaguer to support doctoral students in the field of Mathematics to carry out an international research stay, Call 2020.
