Developing non-interactive MPC with trusted hardware for enhanced security

Secure multiparty computation (MPC) is a promising technology for supporting privacy-preserving computation between multiple untrusted parties. Recent work has made progress reducing the number of online messages that must be sent by each participant to one, in an effort to improve communication overhead. These non-interactive protocols (NI-MPC) are efficient but do not offer standard security guarantees. A vital next step in the research is developing NI-MPC protocols that offer traditional security guarantees in the standard model. This is challenging, because protocols that are non-interactive are vulnerable to the residual function attack, and a malicious party can evaluate a function multiple times using different inputs to deduce the inputs provided by honest users. After proving NI-MPC protocols without extra trust assumptions cannot achieve fully malicious security, fairness, or robustness in the standard model, we solve this problem using trusted hardware. We then present two novel NI-MPC protocols that achieve standard privacy and correctness, and also provide guarantees of fairness and robustness (for the latter additional communication is necessary if an attack occurs). We also introduce the first implementation of an NI-MPC protocol with a one-round online phase that is secure in the standard model. In addition, we rigorously analyze the computational and communication complexity of existing protocols that require either two rounds of communication or one round of online communication. We demonstrate that our protocol outperforms or is comparable to their complexity. Furthermore, we provide rigorous proofs of correctness, security, fairness, and robustness in the covert and malicious adversary models.