Paper 2026/2103 Original: eprint.iacr.org/2026/2103 ↗

LaBinius – Fast Lattice-Based Binary Polynomial Commitment Scheme

Abstract

Lattice-based proof systems are one of the leading routes to quantum-safe succinct proofs. Existing lattice-based schemes come with inherent limitations arising from the coupling between the commitment and constraint domains. First, commitment efficiency is restricted by the need for invertible challenge differences, which precludes the use of fully splitting moduli that enable the fastest lattice arithmetic. Second, the characteristic of the constraint field must equal the commitment modulus. This limits the efficiency of proving binary computations, including standard hash function evaluations. We present $\mathsf{LaBinius}$, a lattice-based polynomial commitment scheme, in which the evaluation arithmetic is separated from that of the commitment. The commitment runs over a composite modulus, and all of its prime factors are NTT-friendly. The evaluation claim lives in a binary extension field, without bitness checks or overhead over a binary arithmetisation. We implement the scheme with AVX-512 kernels and connect it to the $\mathsf{Binius}$ and $\mathsf{Flock}$ front ends in an almost black-box way, which lets us use their arithmetisations tailored to binary fields. As a result, we obtain a SNARK for standard hashes. Proving $\mathsf{Keccak}$-$\mathsf{256}$, $\mathsf{SHA}$-$\mathsf{256}$ and $\mathsf{BLAKE3}$ on one core, our prover takes at most $1.2$ times as long as the hash-based prover supplied with each system, and we obtain a single-core throughput of over $67{,}000$ $\mathsf{BLAKE3}$ compressions per second with verification in under $40$ milliseconds. With $\mathsf{LaBRADOR}$ as a recursive compressor, the prover takes less than twice as long as the hash-based provers at the largest sizes we consider, while the proof size is below $100$ KiB. This is about five times smaller than the proofs of $\mathsf{Binius}$ and $\mathsf{Flock}$ at those sizes and constitutes the smallest quantum-safe proof of a standard hash evaluation to date.