Akin Ünal

dblp:258/9227 · DBLP profile ↗
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7ranked-venue papers
2as first author
6since 2021 · last 2025
0000-0002-8929-0221ORCID · reported

Domains — the database's venue-derived domains; a paper can count in several

Security and privacy · 7 · 2 first-author · 6 since 2021Theory of computation · 2 · 2 since 2021
YearPublicationVenuePosition
2025 On the Soundness of Algebraic Attacks Against Code-Based Assumptions
Miguel Cueto Noval, Simon-Philipp Merz, Patrick Stählin, Akin Ünal
EUROCRYPT (6)4
2025 Constrained Verifiable Random Functions Without Obfuscation and Friends
abstract
CVRFs are PRFs that unify the properties of verifiable and constrained PRFs. Since they were introduced concurrently by Fuchsbauer and Chandran-Raghuraman-Vinayagamurthy in 2014, it has been an open problem to construct CVRFs without using heavy machinery such as multilinear maps, obfuscation or functional encryption. We solve this problem by constructing a prefix-constrained verifiable PRF that does not rely on the aforementioned assumptions. Essentially, our construction is a verifiable version of the Goldreich-Goldwasser-Micali PRF. To achieve verifiability we leverage degree-2 algebraic PRGs and bilinear groups. In short, proofs consist of intermediate values of the Goldreich-Goldwasser-Micali PRF raised to the exponents of group elements. These outputs can be verified using pairings since the underlying PRG is of degree 2. We prove the selective security of our construction under the Decisional Square Diffie-Hellman (DSDH) assumption and a new assumption, which we dub recursive Decisional Diffie-Hellman (recursive DDH). We prove the soundness of recursive DDH in the generic group model assuming the hardness of the Multivariate Quadratic (MQ) problem and a new variant thereof, which we call MQ+. Last, in terms of applications, we observe that our CVRF is also an exponent (C)VRF in the plain model. Exponent VRFs were recently introduced by Boneh et al. (Eurocrypt’25) with various applications to threshold cryptography in mind. In addition to that, we give further applications for prefix-CVRFs in the blockchain setting, namely, stake-pooling and compressible randomness beacons.
Nicholas Brandt, Miguel Cueto Noval, Christoph U. Günther, Akin Ünal, Stella Wohnig
TCC (4)4
2024 Evasive LWE Assumptions: Definitions, Classes, and Counterexamples
Christopher Brzuska, Akin Ünal, Ivy K. Y. Woo
ASIACRYPT (4)2
2024 Lower Bounds for Lattice-Based Compact Functional Encryption
Erkan Tairi, Akin Ünal
EUROCRYPT (2)2
2023 Worst-Case Subexponential Attacks on PRGs of Constant Degree or Constant Locality
Akin Ünal
EUROCRYPT (1)1
2022 The Price of Verifiability: Lower Bounds for Verifiable Random Functions
Nicholas Brandt, Dennis Hofheinz, Julia Kastner 0001, Akin Ünal
TCC (2)4
2020 Impossibility Results for Lattice-Based Functional Encryption Schemes
Akin Ünal
EUROCRYPT (1)1