Our work investigates the question whether it is possible to achieve a reasonable level of input and function privacy simultaneously even in the above cases. We propose the notion of Controlled PFE (CPFE) with different flavours of security and answer the question affirmatively by showing simple, generic realizations of the new notions. Our main construction, based on functional encryption (FE), also enjoys strong reusability properties enabling, e.g. fast computation of the same function on different inputs. To demonstrate the applicability of our approach, we show a concrete instantiation of the FE-based protocol for inner product computation that enables secure statistical analysis (and more) under the standard Decisional Diffie--Hellman assumption.
Category / Keywords: cryptographic protocols / secure computation, private function evaluation, functional encryption Original Publication (with minor differences): ICISC-2019 Date: received 8 Nov 2019, last revised 11 Nov 2019 Contact author: mhorvath at crysys hu Available format(s): PDF | BibTeX Citation Version: 20191111:210442 (All versions of this report) Short URL: ia.cr/2019/1302