Paper 2025/2315
Conditionally Input-Revealing 2PC and Fuzzy Password-Authenticated Key Exchange
Abstract
Yao's famous protocol for secure 2-party computation, based on garbled circuits, is well-known to be insecure against an actively corrupt garbler. We introduce a new and extremely simple variant of Yao's protocol that is fully secure against active adversaries, for a certain class of functions that we call conditionally input-revealing. We then show how to use this new protocol as the basis for fuzzy password authenticated key exchange (fuzzy PAKE). In fuzzy PAKE, two parties each hold a low-entropy secret (e.g., a password), and they interact to obtain a secure high-entropy key if and only if the passwords are sufficiently ``close.'' Our new fuzzy PAKE protocol supports completely arbitrary predicates for password ``closeness''. Compared to prior fuzzy PAKE protocols, ours is roughly $2\times$ cheaper in communication, computation, and round complexity.
Metadata
- Available format(s)
-
PDF
- Category
- Cryptographic protocols
- Publication info
- A major revision of an IACR publication in EUROCRYPT 2026
- Keywords
- PAKE
- Contact author(s)
-
richdavi @ oregonstate edu
rosulekm @ oregonstate edu
xujiay @ oregonstate edu - History
- 2026-02-24: revised
- 2025-12-23: received
- See all versions
- Short URL
- https://ia.cr/2025/2315
- License
-
CC BY
BibTeX
@misc{cryptoeprint:2025/2315,
author = {David Richardson and Mike Rosulek and Jiayu Xu},
title = {Conditionally Input-Revealing {2PC} and Fuzzy Password-Authenticated Key Exchange},
howpublished = {Cryptology {ePrint} Archive, Paper 2025/2315},
year = {2025},
url = {https://eprint.iacr.org/2025/2315}
}
