5 results sorted by ID
Malicious Security for PIR (almost) for Free
Brett Falk, Pratyush Mishra, Matan Shtepel
Foundations
Private Information Retrieval (PIR) enables a client to retrieve a database element from a semi-honest server while hiding the element being queried from the server. Maliciously-secure PIR (mPIR) [Colombo et al., USENIX Security '23] strengthens the guarantees of plain (i.e., semi-honest) PIR by ensuring that even a misbehaving server (a) cannot compromise client privacy via selective-failure attacks, and (b) must answer every query *consistently* (i.e., with respect to the same database)....
SNARGs for Monotone Policy Batch NP
Zvika Brakerski, Maya Farber Brodsky, Yael Tauman Kalai, Alex Lombardi, Omer Paneth
Foundations
We construct a succinct non-interactive argument ($\mathsf{SNARG}$) for the class of monotone policy batch $\mathsf{NP}$ languages under the Learning with Errors ($\mathsf{LWE}$) assumption. This class is a subclass of $\mathsf{NP}$ that is associated with a monotone function~$f:\{0,1\}^k\rightarrow\{0,1\}$ and an $\mathsf{NP}$ language $\mathcal L$, and contains instances $(x_1,\ldots,x_k)$ such that $f(b_1,\ldots,b_k)=1$ where $b_j=1$ if and only if $x_j\in \mathcal L$. Our...
Somewhere Statistical Soundness, Post-Quantum Security, and SNARGs
Yael Tauman Kalai, Vinod Vaikuntanathan, Rachel Yun Zhang
Foundations
The main conceptual contribution of this paper is a unification of two leading paradigms for constructing succinct argument systems, namely Kilian's protocol and the BMW (Biehl-Meyer-Wetzel) heuristic. We define the notion of a multi-extractable somewhere statistically binding (meSSB) hash family, an extension of the notion of somewhere statistically binding hash functions (Hubacek and Wichs, ITCS 2015), and construct it from LWE. We show that when instantiating Kilian's protocol with a...
The Parallel Repetition of Non-Signaling Games: Counterexamples and Dichotomy
Justin Holmgren, Lisa Yang
Foundations
Non-signaling games are an important object of study in the theory of
computation, for their role both in quantum information and in (classical)
cryptography. In this work, we study the behavior of these games under
parallel repetition.
We show that, unlike the situation both for classical games and for
two-player non-signaling games, there are $k$-player
non-signaling games (for $k \ge 3$) whose values do not tend to $0$ with
sufficient parallel repetition. In fact, parallel repetition...
Multi-Prover Commitments Against Non-Signaling Attacks
Serge Fehr, Max Fillinger
Foundations
We reconsider the concept of two-prover (and more generally: multi-prover) commitments, as introduced in the late eighties in the seminal work by Ben-Or et al. As was recently shown by Crëpeau et al., the security of known two-prover commitment schemes not only relies on the explicit assumption that the two provers cannot communicate, but also depends on what their information processing capabilities are. For instance, there exist schemes that are secure against classical provers but...
Private Information Retrieval (PIR) enables a client to retrieve a database element from a semi-honest server while hiding the element being queried from the server. Maliciously-secure PIR (mPIR) [Colombo et al., USENIX Security '23] strengthens the guarantees of plain (i.e., semi-honest) PIR by ensuring that even a misbehaving server (a) cannot compromise client privacy via selective-failure attacks, and (b) must answer every query *consistently* (i.e., with respect to the same database)....
We construct a succinct non-interactive argument ($\mathsf{SNARG}$) for the class of monotone policy batch $\mathsf{NP}$ languages under the Learning with Errors ($\mathsf{LWE}$) assumption. This class is a subclass of $\mathsf{NP}$ that is associated with a monotone function~$f:\{0,1\}^k\rightarrow\{0,1\}$ and an $\mathsf{NP}$ language $\mathcal L$, and contains instances $(x_1,\ldots,x_k)$ such that $f(b_1,\ldots,b_k)=1$ where $b_j=1$ if and only if $x_j\in \mathcal L$. Our...
The main conceptual contribution of this paper is a unification of two leading paradigms for constructing succinct argument systems, namely Kilian's protocol and the BMW (Biehl-Meyer-Wetzel) heuristic. We define the notion of a multi-extractable somewhere statistically binding (meSSB) hash family, an extension of the notion of somewhere statistically binding hash functions (Hubacek and Wichs, ITCS 2015), and construct it from LWE. We show that when instantiating Kilian's protocol with a...
Non-signaling games are an important object of study in the theory of computation, for their role both in quantum information and in (classical) cryptography. In this work, we study the behavior of these games under parallel repetition. We show that, unlike the situation both for classical games and for two-player non-signaling games, there are $k$-player non-signaling games (for $k \ge 3$) whose values do not tend to $0$ with sufficient parallel repetition. In fact, parallel repetition...
We reconsider the concept of two-prover (and more generally: multi-prover) commitments, as introduced in the late eighties in the seminal work by Ben-Or et al. As was recently shown by Crëpeau et al., the security of known two-prover commitment schemes not only relies on the explicit assumption that the two provers cannot communicate, but also depends on what their information processing capabilities are. For instance, there exist schemes that are secure against classical provers but...
