Paper 2025/1433
A Fully-Adaptive Threshold Partially-Oblivious PRF
, Friedrich-Alexander-Universität Erlangen-Nürnberg, TU Wien, University of Stuttgart, TU WienAbstract
Oblivious Pseudorandom Functions (OPRFs) are fundamental cryptographic primitives essential for privacy-enhancing technologies such as private set intersection, oblivious keyword search, and password-based authentication protocols. We present the first fully adaptive, partially oblivious threshold pseudorandom function that supports proactive key refresh and provides composable security under the One-More Gap Diffie-Hellman assumption in the random oracle model. Our construction is secure with respect to a new ideal functionality for OPRFs that addresses three critical shortcomings of previous models–specifically, key refresh and non-verifiability issues that rendered them unrealizable. In addition, we identify a gap in a prior work's proof of partial obliviousness and develop a novel proof technique to salvage their scheme.
Metadata
- Available format(s)
-
PDF
- Category
- Cryptographic protocols
- Publication info
- A minor revision of an IACR publication in CRYPTO 2025
- Keywords
- Partially-Oblivious PRFThreshold CryptographyAdaptive SecurityUniversal Composability
- Contact author(s)
-
ruben baecker @ fau de
paul gerhart @ tuwien ac at
daniel rausch @ sec uni-stuttgart de
dominique schroeder @ tuwien ac at - History
- 2025-08-07: approved
- 2025-08-06: received
- See all versions
- Short URL
- https://ia.cr/2025/1433
- License
-
CC BY
BibTeX
@misc{cryptoeprint:2025/1433,
author = {Ruben Baecker and Paul Gerhart and Daniel Rausch and Dominique Schröder},
title = {A Fully-Adaptive Threshold Partially-Oblivious {PRF}},
howpublished = {Cryptology {ePrint} Archive, Paper 2025/1433},
year = {2025},
url = {https://eprint.iacr.org/2025/1433}
}
