cronokirby

(2026-03) -mathsf{GlueLUT}; Generalized Lookup Table Arguments over Residue Rings via Auxiliary Fields

2026-03-10

Abstract

Lookup Table (LUT) arguments are a central efficiency primitive in modern SNARKs, and existing high-performance constructions are largely tailored to large fields. Meanwhile, an increasingly important class of applications is natively ring-based, with arithmetic carried out over residue rings ZQ:=Z/QZ\mathbb{Z}_Q:=\mathbb{Z}/Q\mathbb{Z}. We find that naively extending field-based lookup table techniques to rings faces fundamental obstacles, which can lead to unsoundness, limited applicability, or poor efficiency.

We introduce GlueLUT\mathsf{GlueLUT}, a general framework for constructing LUT arguments over arbitrary residue ring ZQ\mathbb{Z}_Q that supports arbitrary tables. Our main technical tool is a new primitive called Cross-Modulus Consistency (CMC) PIOP, proves that two witnesses defined over coprime moduli share the same underlying integer in the canonical range. Using our CMC PIOP as a glue, we perform the lookups over an auxiliary field FP\mathbb{F}_P (for a prime P>QP>Q) and then certify the consistency between the witness over ZQ\mathbb{Z}_Q and the witness over FP\mathbb{F}_P, thereby avoiding the obstacles of constructing LUT arguments directly over rings. We further provide two optimized instantiations, GlueLUT\mathsf{GlueLUT}-v1\mathsf{v1} for Q=pqQ=pq and GlueLUT\mathsf{GlueLUT}-v2\mathsf{v2} for Q=pkQ=p^k, capturing common modulus families in practice. Finally, we implement GlueLUT\mathsf{GlueLUT}-v1\mathsf{v1} and GlueLUT\mathsf{GlueLUT}-v2\mathsf{v2} as stand-alone PIOPs and report prototype results that corroborate our theoretical efficiency.