Our primitive comes with a series of extra features as follows: 1) there is a one-time setup procedure for all circuits; 2) senders do not need to be aware of the functions which will be evaluated on the encrypted data, nor do they need to register keys; 3) tokens are independent of senders and receiver; and 4) receivers are able to verify the correctness of computation given short auxiliary information on the input data and the function, independently of the complexity of the computed circuit.
We give a modular construction of such a DHE scheme from three components: Fully Homomorphic Encryption (FHE), Functional Encryption (FE), and a (customised) MAC. As a stepping stone, we first define Verifiable Functional Encryption (VFE), and then show how one can build a secure DHE scheme from a VFE and an FHE scheme. We also show how to build the required VFE from a standard FE together with a MAC scheme. All our results hold in the standard model.
Finally, we show how one can build a verifiable computation (VC) scheme generically from a DHE. As a corollary, we get the first VC scheme which remains verifiable even if the attacker can observe verification results.Category / Keywords: Homomorphism Delegation. Homomorphic Encryption. Functional Encryption. Verifiable Computation. Public-Key Cryptography. Provable Security. Date: received 3 May 2011, last revised 29 Aug 2011 Contact author: mbb at di uminho pt, pooya farshim@gmail com Available format(s): PDF | BibTeX Citation Version: 20110829:142617 (All versions of this report) Short URL: ia.cr/2011/215 Discussion forum: Show discussion | Start new discussion