In this work, we propose a novel framework that realizes VE protocols using the MPC-in-the-head zero-knowledge proof systems (Ishai et al. STOC 2007). Our generic compiler can turn a large class of MPC-in-the-head ZK proofs into secure VE protocols for any CPA secure public-key encryption (PKE) schemes with the undeniability property, a notion that essentially guarantees binding of encryption when used as a commitment scheme.
Our framework is versatile: because the circuit proven by the MPC-in-the-head prover is decoupled from a complex encryption function, the prover’s work can be focused on proving properties (i.e. relation) about the encrypted data, not the proof of plaintext knowledge. Hence, our approach allows for instantiation with various combinations of properties about encrypted data and encryption functions. As concrete applications we describe new approaches to verifiably encrypting discrete logarithms in any prime order group and AES private keys.
Category / Keywords: verifiable encryption, zero knowledge proof, MPC-in-the-head Date: received 31 Dec 2021 Contact author: takahashi at cs au dk, gregz at microsoft com Available format(s): PDF | BibTeX Citation Version: 20211231:122507 (All versions of this report) Short URL: ia.cr/2021/1704