Audit-by-Construction: A Self-Executing Smart Contract Architecture on Permissioned Distributed Ledgers for the Verifiable Settlement of Civil Engineering Works under Peruvian Public-Procurement Law

Abstract

Abstract Civil engineering obras públicas (public works) in Andean procurement systems still resolve their settlement ( liquidación ) through paper binders, manual valorizaciones and notary-mediated arbitration, generating an average certification cycle of 60 to 90 days per milestone [1, 2]. This article designs and qualifies a self-executing smart contract framework deployed on permissioned distributed ledger infrastructure for the verifiable settlement of construction payments, aligned with Peruvian Ley N° 30225, its Reglamento (D.S. N° 344-2018-EF) and the technical norm D.S. N° 011-79-VC (Fórmula Polinómica). A documentary mixed-methods design was adopted, combining (i) systematic review of regulatory and peer-reviewed sources, (ii) a six-attribute by three-regime comparative matrix anchored to quantitative evidence already documented in the literature, (iii) a four-layer audit-by-construction architectural diagram, and (iv) the formal encoding of three Peruvian public-works settlement formulas (price adjustment K, daily penalty P, and final settlement L) as auditable bytecode logic. Three findings are reported: (1) the on-chain verification window for a milestone-triggered disbursement contracts from a literature-documented baseline of 67 days [9] to a theoretical 3.9–4.2 minutes under Hyperledger Fabric with Raft consensus, consistent with benchmarks reported by Yang et al. [5] and Ahmadisheykhsarmast and Sonmez [7]; (2) the F-Polynomial, the 0.10·M/F·t penalty, and the L = M + R − D − A − P − Pc settlement identity become reproducible inside contract bytecode without altering their legal substance; (3) the regulatory gap between academic blockchain prototypes and Peruvian public procurement narrows through a pattern in which each physical milestone is captured on-chain by an immutable evidence row before any monetary disbursement is triggered. The contribution is operational rather than legislative: a reusable architecture that brings cryptographically verifiable evidence to the liquidación de obra process without requiring statutory reform. As the study relied exclusively on public regulatory documents, peer-reviewed literature and open-source code — with no human participants or personal data — it was exempted from full ethics committee review under the Universidad Autónoma del Perú research-ethics protocol for documentary and non-experimental studies.