Cryptology ePrint Archive: Report 2014/989

Controlled Homomorphic Encryption: Definition and Construction

Yvo Desmedt and Vincenzo Iovino and Giuseppe Persiano and Ivan Visconti

Abstract: In this work we put forth the notion of a Controllable Homomorphic Encryption scheme (CHES), a new primitive that includes features of both FHEs and FunctEs. In a CHES it is possible (similarly to a FHE) to homomorphically evaluate a ciphertext Ct = Enc(m) and a circuit C therefore obtaining Enc(C(m)) but only if (similarly to a FunctE) a token for C has been received from the owner of the secret key. We discuss difficulties in constructing a CHES and then show a construction based on any FunctE. As a byproduct our CHES also represents a FunctE supporting the re-encryption functionality and in that respect improves existing solutions.

Category / Keywords: Functional Encryption, Non-malleability, Fully Homomorphic Encryption

Original Publication (with minor differences): WAHC '17 (FC Workshop)

Date: received 10 Dec 2014, last revised 16 Feb 2017

Contact author: vinciovino at gmail com

Available format(s): PDF | BibTeX Citation

Note: In this eprint version we clarify the relation with previous works on functional encryption for randomized functionalities and related primitives

Version: 20170216:094309 (All versions of this report)

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