Our approach relies on ``multi-key fully homomorphic encryption (MFHE)", introduced by Lopez-Alt et al. (STOC '12), which enables homomorphic computation over data encrypted under different keys. We present a construction of MFHE based on LWE that significantly simplifies a recent scheme of Clear and McGoldrick (CRYPTO '15). We then extend this construction to allow for a one-round distributed decryption of a multi-key ciphertext. Our entire MPC protocol consists of the following two rounds:
1. Each party individually encrypts its input under its own key and broadcasts the ciphertext. All parties can then homomorphically compute a multi-key encryption of the output.
2. Each party broadcasts a partial decryption of the output using its secret key. The partial decryptions can be combined to recover the output in plaintext.Category / Keywords: public-key cryptography / Full Homomorphic Encryption, MPC Date: received 16 Apr 2015, last revised 27 Feb 2016 Contact author: pratyay85 at gmail com Available format(s): PDF | BibTeX Citation Version: 20160228:035202 (All versions of this report) Short URL: ia.cr/2015/345 Discussion forum: Show discussion | Start new discussion