Paper 2026/437
Efficient Single-Server Stateful PIR Using Format-Preserving Encryption
Abstract
Recently, Stateful Private Information Retrieval (PIR) has emerged as a promising new paradigm of PIR. Despite significant recent progress, state-of-the-art single-server schemes in this paradigm still suffer from practical inefficiencies in communication, computation, and/or client storage. In this work, we construct a new single-server stateful PIR scheme called HarmonyPIR that achieves efficient communication, computation, and client storage. From a technical standpoint, we build on the recent work of Wang and Ren (EUROCRYPT 25) and propose a new hint organization that uses only a single random permutation. The random permutation can be instantiated using either AES or the recently standardized FF1 Format-Preserving Encryption, yielding two variants of HarmonyPIR. Our new scheme achieves up to two orders of magnitude better amortized computation and up to five times better amortized communication than state-of-the-art schemes.
Metadata
- Available format(s)
-
PDF
- Category
- Cryptographic protocols
- Publication info
- Preprint.
- Keywords
- Private Information RetrievalStateful Private Information Retrieval
- Contact author(s)
-
psa3 @ illinois edu
renling @ illinois edu - History
- 2026-03-05: approved
- 2026-03-03: received
- See all versions
- Short URL
- https://ia.cr/2026/437
- License
-
CC BY
BibTeX
@misc{cryptoeprint:2026/437,
author = {Pranav Shriram Arunachalaramanan and Ling Ren},
title = {Efficient Single-Server Stateful {PIR} Using Format-Preserving Encryption},
howpublished = {Cryptology {ePrint} Archive, Paper 2026/437},
year = {2026},
url = {https://eprint.iacr.org/2026/437}
}
