MATHEMATICS AND STATISTICS COLLOQUIUM – Private communication via finite geometry
Padraig O. Cathain, Worcester Polytechnic Institute
Monday, April 30, starting at 4:00 pm, Davis 301
Refreshments at 3:30 pm, Davis 2nd floor
In a User-Private Information Retrieval (UPIR) scheme, a set of users collaborate to retrieve files from a database without revealing to an external observer which user in the scheme requested a particular file. UPIR protocols have been proposed in the literature based on projective planes and symmetric designs. In this talk I will explain the goals of private communication, and show that all UPIR schemes described in the literature can be compromised by the defection of a coalition of at most three users.
In recent work with collaborators from Finland, Italy and the USA, we proposed a new class of schemes based on generalized quadrangles which remain secure with high probability even after the defection of the fourth root of the number of users. I will define and describe all necessary concepts in the talk – no background knowledge of finite geometry or cryptography will be assumed. The talk will be accessible to advanced undergraduates.