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Main Authors: Lee, Sungmin, Lee, Kichang, Han, Gyeongmin, Ko, JeongGil
Format: Preprint
Published: 2025
Subjects:
Online Access:https://arxiv.org/abs/2512.24238
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author Lee, Sungmin
Lee, Kichang
Han, Gyeongmin
Ko, JeongGil
author_facet Lee, Sungmin
Lee, Kichang
Han, Gyeongmin
Ko, JeongGil
contents Many location-based services rely on a point-in-polygon test (PiP), checking whether a point or a trajectory lies inside a geographic zone. Since geometric operations are expensive in zero-knowledge proofs, privately performing the PiP test is challenging. In this paper, we answer the research questions of how different ways of encoding zones affect accuracy and proof cost by exploiting gridbased lookup tables under a fixed STARK execution model. Beyond a Boolean grid-based baseline that marks cells as in- or outside, we explore a distance-aware encoding approach that stores how far each cell is from a zone boundary and uses interpolation to reason within a cell. Our experiments on real-world data demonstrate that the proposed distance-aware approach achieves higher accuracy on coarse grids (max. 60%p accuracy gain) with only a moderate verification overhead (approximately 1.4x), making zone encoding the key lever for efficient zero-knowledge spatial checks.
format Preprint
id arxiv_https___arxiv_org_abs_2512_24238
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Spatial Discretization for Fine-Grain Zone Checks with STARKs
Lee, Sungmin
Lee, Kichang
Han, Gyeongmin
Ko, JeongGil
Cryptography and Security
Many location-based services rely on a point-in-polygon test (PiP), checking whether a point or a trajectory lies inside a geographic zone. Since geometric operations are expensive in zero-knowledge proofs, privately performing the PiP test is challenging. In this paper, we answer the research questions of how different ways of encoding zones affect accuracy and proof cost by exploiting gridbased lookup tables under a fixed STARK execution model. Beyond a Boolean grid-based baseline that marks cells as in- or outside, we explore a distance-aware encoding approach that stores how far each cell is from a zone boundary and uses interpolation to reason within a cell. Our experiments on real-world data demonstrate that the proposed distance-aware approach achieves higher accuracy on coarse grids (max. 60%p accuracy gain) with only a moderate verification overhead (approximately 1.4x), making zone encoding the key lever for efficient zero-knowledge spatial checks.
title Spatial Discretization for Fine-Grain Zone Checks with STARKs
topic Cryptography and Security
url https://arxiv.org/abs/2512.24238