A Fully-Adaptive Threshold Partially-Oblivious PRF

Baecker R, Gerhart P, Rausch D, Schröder D (2025)

Publication Type: Conference contribution

Publication year: 2025

Journal

Lecture Notes in Computer Science Springer Verlag

Publisher: Springer Science and Business Media Deutschland GmbH

Book Volume: 16004 LNCS

Pages Range: 569-597

Conference Proceedings Title: Lecture Notes in Computer Science

Event location: Santa Barbara, CA US

ISBN: 9783032019004

DOI: 10.1007/978-3-032-01901-1_18

Abstract

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.

Authors with CRIS profile

Ruben Baecker Lehrstuhl für Informatik 13 (Angewandte Kryptographie) Dominique Schröder Lehrstuhl für Informatik 13 (Angewandte Kryptographie)

Involved external institutions

Universität Stuttgart DE Germany (DE) Technische Universität Wien / Vienna University of Technology AT Austria (AT)

How to cite

APA:

Baecker, R., Gerhart, P., Rausch, D., & Schröder, D. (2025). A Fully-Adaptive Threshold Partially-Oblivious PRF. In Yael Tauman Kalai, Seny F. Kamara (Eds.), Lecture Notes in Computer Science (pp. 569-597). Santa Barbara, CA, US: Springer Science and Business Media Deutschland GmbH.

MLA:

Baecker, Ruben, et al. "A Fully-Adaptive Threshold Partially-Oblivious PRF." Proceedings of the 45th Annual International Cryptology Conference, CRYPTO 2025, Santa Barbara, CA Ed. Yael Tauman Kalai, Seny F. Kamara, Springer Science and Business Media Deutschland GmbH, 2025. 569-597.

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