[Resource Topic] 2021/864: A Fast and Simple Partially Oblivious PRF, with Applications

Welcome to the resource topic for 2021/864

Title:
A Fast and Simple Partially Oblivious PRF, with Applications

Authors: Nirvan Tyagi, Sofı́a Celi, Thomas Ristenpart, Nick Sullivan, Stefano Tessaro, Christopher A. Wood

Abstract:

We build the first construction of a partially oblivious pseudorandom function (POPRF) that does not rely on bilinear pairings. Our construction can be viewed as combining elements of the 2HashDH OPRF of Jarecki, Kiayias, and Krawczyk with the Dodis-Yampolskiy PRF. We analyze our POPRF’s security in the random oracle model via reduction to a new one-more gap strong Diffie-Hellman inversion assumption. The most significant technical challenge is establishing confidence in the new assumption, which requires new proof techniques that enable us to show that its hardness is implied by the q-DL assumption in the algebraic group model. Our new construction is as fast as the current, standards-track OPRF 2HashDH protocol, yet provides a new degree of flexibility useful in a variety of applications. We show how POPRFs can be used to prevent token hoarding attacks against Privacy Pass, reduce key management complexity in the OPAQUE password authenticated key exchange protocol, and ensure stronger security for password breach alerting services.

ePrint: https://eprint.iacr.org/2021/864

Talk: https://www.youtube.com/watch?v=ScKjb7JFhhw

Slides: https://iacr.org/submit/files/slides/2022/eurocrypt/eurocrypt2022/138/slides.pdf

See all topics related to this paper.

Feel free to post resources that are related to this paper below.

Example resources include: implementations, explanation materials, talks, slides, links to previous discussions on other websites.

For more information, see the rules for Resource Topics .