activity
20192025
most citedFair Coin Flipping: Tighter Analysis and the Many-Party Case

23 citations · 60 across the 15 of their papers we have counts for

collaborators

22 papers

cs.CR2025

Computationally Differentially Private Inner Product Protocols Imply Oblivious Transfer

Iftach Haitner, Noam Mazor, Jad Silbak +2

In distributed differential privacy, multiple parties collaborate to analyze their combined data while each party protects the confidentiality of its data from the others. Interest…

cs.CR2021

On the Complexity of Two-Party Differential Privacy

Iftach Haitner, Noam Mazor, Jad Silbak +1

In distributed differential privacy, the parties perform analysis over their joint data while preserving the privacy for both datasets. Interestingly, for a few fundamental two-par…

cs.CC2021

Channels of Small Log-Ratio Leakage and Characterization of Two-Party Differentially Private Computation

Iftach Haitner, Noam Mazor, Ronen Shaltiel +1

Consider a PPT two-party protocol in which the parties get no private inputs and obtain outputs , and let and denote the parties' individu…

cs.CC2021

Lower Bounds on the Time/Memory Tradeoff of Function Inversion

Dror Chawin, Iftach Haitner, Noam Mazor

We study time/memory tradeoffs of function inversion: an algorithm, i.e., an inverter, equipped with an s-bit advice on a randomly chosen function and using or…

cs.CR2021

On the Communication Complexity of Key-Agreement Protocols

Iftach Haitner, Noam Mazor, Rotem Oshman +2

Key-agreement protocols whose security is proven in the random oracle model are an important alternative to protocols based on public-key cryptography. In the random oracle model,…

cs.CR2021

From Fairness to Full Security in Multiparty Computation

Ran Cohen, Iftach Haitner, Eran Omri +1

In the setting of secure multiparty computation (MPC), a set of mutually distrusting parties wish to jointly compute a function, while guaranteeing the privacy of their inputs and…

cs.CR2021

Computational Two-Party Correlation: A Dichotomy for Key-Agreement Protocols

Iftach Haitner, Kobbi Nissim, Eran Omri +2

Let be an efficient two-party protocol that given security parameter , both parties output single bits and , respectively. We are interested in how "a…

cs.CR2021

Inaccessible Entropy II: IE Functions and Universal One-Way Hashing

Iftach Haitner, Thomas Holenstein, Omer Reingold +2

This paper uses a variant of the notion of \emph{inaccessible entropy} (Haitner, Reingold, Vadhan and Wee, STOC 2009), to give an alternative construction and proof for the fundame…

cs.CR2021★ 16 cited

Finding Collisions in Interactive Protocols -- Tight Lower Bounds on the Round and Communication Complexities of Statistically Hiding Commitments

Iftach Haitner, Jonathan J. Hoch, Omer Reingold +1

We study the round and communication complexities of various cryptographic protocols. We give tight lower bounds on the round and communication complexities of any fully black-box…

cs.CR2021

Hardness-Preserving Reductions via Cuckoo Hashing

Itay Berman, Iftach Haitner, Ilan Komargodski +1

The focus of this work is \emph{hardness-preserving} transformations of somewhat limited pseudorandom functions families (PRFs) into ones with more versatile characteristics. Consi…

cs.CR2021

Coin Flipping of \emph{Any} Constant Bias Implies One-Way Functions

Itay Berman, Iftach Haitner, Aris Tentes

We show that the existence of a coin-flipping protocol safe against \emph{any} non-trivial constant bias (\eg ) implies the existence of one-way functions. This improves upon…

cs.CR2021

An Almost-Optimally Fair Three-Party Coin-Flipping Protocol

Iftach Haitner, Eliad Tsfadia

In a multiparty fair coin-flipping protocol, the parties output a common (close to) unbiased bit, even when some corrupted parties try to bias the output. Cleve [STOC 1986] has sho…

cs.CR2021★ 8 cited

Characterization of Secure Multiparty Computation Without Broadcast

Ran Cohen, Iftach Haitner, Eran Omri +1

A major challenge in the study of cryptography is characterizing the necessary and sufficient assumptions required to carry out a given cryptographic task. The focus of this work i…

cs.CR2021

A Tight Parallel Repetition Theorem for Partially Simulatable Interactive Arguments via Smooth KL-Divergence

Itay Berman, Iftach Haitner, Eliad Tsfadia

Hardness amplification is a central problem in the study of interactive protocols. While ``natural'' parallel repetition transformation is known to reduce the soundness error of so…

cs.CR2021

On the Complexity of Fair Coin Flipping

Iftach Haitner, Nikolaos Makriyannis, Eran Omri

A two-party coin-flipping protocol is -fair if no efficient adversary can bias the output of the honest party (who always outputs a bit, even if the other party aborts) by more…

cs.CR2021

Tighter Bounds on Multi-Party Coin Flipping via Augmented Weak Martingales and Differentially Private Sampling

Amos Beimel, Iftach Haitner, Nikolaos Makriyannis +1

In his seminal work, Cleve [STOC '86] has proved that any -round coin-flipping protocol can be efficiently biased by . This lower bound was met for the two-party case by…

cs.CR2021

Distributional Collision Resistance Beyond One-Way Functions

Nir Bitansky, Iftach Haitner, Ilan Komargodski +1

Distributional collision resistance is a relaxation of collision resistance that only requires that it is hard to sample a collision where is uniformly random and i…

cs.CR2021★ 23 cited

Fair Coin Flipping: Tighter Analysis and the Many-Party Case

Niv Buchbinder, Iftach Haitner, Nissan Levi +1

In a multi-party fair coin-flipping protocol, the parties output a common (close to) unbiased bit, even when some adversarial parties try to bias the output. In this work we focus…

cs.CR2020★ 2 cited

Inaccessible Entropy I: Inaccessible Entropy Generators and Statistically Hiding Commitments from One-Way Functions

Iftach Haitner, Omer Reingold, Salil Vadhan +1

We put forth a new computational notion of entropy, measuring the (in)feasibility of sampling high-entropy strings that are consistent with a given generator. Specifically, the i't…

cs.CR2020

On the Round Complexity of the Shuffle Model

Amos Beimel, Iftach Haitner, Kobbi Nissim +1

The shuffle model of differential privacy was proposed as a viable model for performing distributed differentially private computations. Informally, the model consists of an untrus…

cs.CR2020

A Tight Lower Bound on Adaptively Secure Full-Information Coin Flip

Iftach Haitner, Yonatan Karidi-Heller

In a distributed coin-flipping protocol, Blum [ACM Transactions on Computer Systems '83], the parties try to output a common (close to) uniform bit, even when some adversarially ch…

cs.CR2019★ 11 cited

On the Round Complexity of Randomized Byzantine Agreement

Ran Cohen, Iftach Haitner, Nikolaos Makriyannis +2

We prove lower bounds on the round complexity of randomized Byzantine agreement (BA) protocols, bounding the halting probability of such protocols after one and two rounds. In part…