Network-Agnostic Multi-party Computation Revisited (Extended Abstract)

Network-Agnostic Multi-party Computation Revisited (Extended Abstract)

연구 분야: Networking

학회: IACR International Conference on Public-Key Cryptography

We study network-agnostic secure multi-party computation (MPC) in the presence of computationally-bounded adversaries. A network-agnostic protocol provides the best possible security guarantees, irrespective of the type of underlying communication network. Previous MPC protocols in this regime either assume a setup for a common reference string (CRS) and a threshold additively homomorphic encryption (Blum et al. CRYPTO 2020) or a plain public-key infrastructure (PKI) setup (Bacho et al. CRYPTO 2023). Both these MPC protocols perform circuit-evaluation over encrypted data and also deploy different forms of zero-knowledge (ZK) proofs, along with other computationally-expensive cryptographic machinery. We aim to build an MPC protocol based on circuit evaluation on secret-shared data, avoiding ZK proofs and other computationally-expensive cryptographic machinery and based on a plain PKI setup. To achieve our goal, we present the first network-agnostic verifiable secret sharing (VSS) protocol with the optimal threshold conditions, which is of independent interest. Previously, network-agnostic VSS is known either with perfect security (Appan et al. IEEE IT 2023) where the threshold conditions are not known to be optimal or with statistical security (Appan et al. TCC 2023) where the threshold conditions are optimal, but the parties need to perform exponential amount of computation and communication. Although our proposed MPC protocol incurs higher communication complexity compared to state-of-the-art network-agnostic MPC protocols, it offers valuable insights and motivates alternative directions for designing computationally inexpensive MPC protocols, based on a plain PKI setup, which has not been explored in the domain of network-agnostic MPC.