Practical and Efficient MPC from FHE, without ZKPoKs

Fully Homomorphic Encryption (FHE) enables one to implement low-round and low-communication complexity Multi-Party Computation (MPC) which is secure in the static malicious corruption model. By expanding on an idea presented in the full version of the FHE-based MPC protocol of Smart (IMA, 2023), we show how to completely remove the need for Zero-Knowledge Proofs-of-Knowledge in that protocol. This simplification makes the final security proof of the MPC protocol much simpler, and more modular. The new protocol makes use of an FHE scheme with an encrypted PRF functionality, and in addition to our main result we formalize the security of such encrypted PRFs and prove the construction of Deo et al. (CCS 2025) secure in this model.