Séminaire des équipes de recherche
Constrained Pseudorandom Functions
- Date : 10/09/2015
- Place : Ecole Normale Supérieure - Salle W - Paris -- 10h30
- Guest(s) : Dennis Hofheinz (Karlsruher Institut für Technologie (KIT)
Pseudorandom functions (PRFs) are universal and very useful cryptographic building blocks. In a nutshell, a PRF is an object that is computationally indistinguishable from a truly random function, but has a short description (also called the PRF key). In 2013, three teams of researchers independently proposed a strengthening of the PRF concept, dubbed "constrained PRFs (CPRFs)". A CPRF is a PRF with the additional property that the key necessary to evaluate the PRF can be constrained to certain sets of inputs.
This talk outlines the definition, existing constructions, and applications of constrained pseudorandom functions. A particular emphasis is put on the notion of "adaptive" CPRFs, i.e., CPRFs that are secure in an environment in which the sets to which keys are constrained are determined adaptively, possibly depending on previous constrained keys.