We formalize the notion of verifiable function encryption and, following prior work in the area, put forth a simulation-based and an indistinguishability-based notion of security. We show that simulation-based verifiable functional encryption is unconditionally impossible even in the most basic setting where there may only be a single key and a single ciphertext. We then give general positive results for the indistinguishability setting: a general compiler from any functional encryption scheme into a verifiable functional encryption scheme with the only additional assumption being the Decision Linear Assumption over Bilinear Groups (DLIN). We also give a generic compiler in the secret-key setting for functional encryption which maintains both message privacy and function privacy. Our positive results are general and also apply to other simpler settings such as Identity-Based Encryption, Attribute-Based Encryption and Predicate Encryption. We also give an application of verifiable functional encryption to the recently introduced primitive of functional commitments.
Finally, in the context of indistinguishability obfuscation, there is a fundamental question of whether the correct program was obfuscated. In particular, the recipient of the obfuscated program needs a guarantee that the program indeed does what it was intended to do. This question turns out to be closely related to verifiable functional encryption. We initiate the study of verifiable obfuscation with a formal definition and construction of verifiable indistinguishability obfuscation.Category / Keywords: public-key cryptography / Functional Encryption, Attribute Based Encryption, Predicate Encryption, Indistinguishability Obfuscation. Date: received 17 Jun 2016 Contact author: saikrishna at cs ucla edu, aayushjainiitd@gmail com Available format(s): PDF | BibTeX Citation Version: 20160617:192632 (All versions of this report) Short URL: ia.cr/2016/629 Discussion forum: Show discussion | Start new discussion