Poster: Framework for Semi-private Function Evaluation with Application to Secure Insurance Rate Calculation

Private Function Evaluation (PFE) allows two parties to jointly compute a private function provided by one party on the secret input of the other party. However, in many applications it is not required to hide the whole function, which is called Semi-Private Function Evaluation (SPFE). In this work, we develop a framework for SPFE which allows to split a function into public and private parts. We show the practicability of using SPFE in a real world scenario by developing a car insurance application for computing user-specific tariffs. We evaluate the performance of our SPFE framework on this concrete example which results in a circuit consisting of 377032 AND gates which improves over PFE by a factor of 9x.