Polynomial commitment schemes (PCSs) are a fundamental cryptographic primitive that allows a prover to reveal evaluations for a committed polynomial. Motivated by the inefficiency of proof generation for large-scale computations as well as the concerns regarding third-party reliance and quantum threats, a line of recent works has focused on distributing code-based PCS, where the proving workload is distributed among multiple sub-provers to accelerate proof generation, while preserving transparent setup and plausible quantum resilience. However, for sub-provers generating an evaluation proof for a polynomial of size , existing solutions either require total communication among sub-provers, or incur an overhead in proof size.
In this paper, we introduce , a novel distribution framework for code-based multilinear PCS, which for the first time achieves communication cost sublinear in , and eliminates the dependence of proof size on the number of sub-provers, without compromising proving speed or security. At its core is a customized proof aggregation method from interleaved code that efficiently combines sub-proofs via minimum communication. We further present two instantiations of : one based on Reed-Solomon code, , achieves proving time, communication, and proof size; the other based on the fast linear code from Brakedown (Golovnev et al., CRYPTO 2023), , features proving time, communication, and proof size for , while enjoying field agnosticity.
We also implement both schemes in Rust and conduct a comprehensive performance evaluation. The experimental results demonstrate their linear scalability with increasing . More specifically, for and , takes 74.8s for proof generation, achieving a 5.18 speedup compared to running a single prover, while generates a proof in 26.9s and achieves a 7.02 speedup.