Cryptology ePrint Archive: Report 2014/989

Controlled Homomorphic Encryption: Definition and Construction

Yvo Desmedt and Vincenzo Iovino and Giuseppe Persiano and Ivan Visconti

Abstract: Fully Homomorphic Encryption schemes (FHEs) and Functional Encryption schemes (FunctEs) have a tremendous impact in Cryptography both for the natural questions that they address and for the wide range of applications in which they have been (sometimes critically) used. 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.

Category / Keywords: unctional enncryption, non-malleability, fully homomorphic encryption

Date: received 10 Dec 2014, last revised 6 Mar 2015

Contact author: vincenzo iovino at uni lu

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: 20150306:122300 (All versions of this report)

Short URL: ia.cr/2014/989

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