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A list of all the posts and pages found on the site. For you robots out there, there is an XML version available for digesting as well.
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Synchronous consensus with optimal asynchronous fallback guarantees
Published in TCC '19: Theory of Cryptography Conference, 2019
This paper (joint with Jonathan Katz and Julian Loss) initiates the study of the network-agnostic model, where the network may be either synchronous (with a higher number of faulty parties) or asynchronous (with a lower number of faulty parties), but parties don’t know which. We show a protocol for Byzantine agreement that tolerates \(t_s\) faults in the synchronous case and \(t_a\) faults in the asynchronous case for any (fixed) \(t_s,t_a\) such that \(2t_s+t_a<n\), where \(n\) is the number of parties, and prove that this tradeoff is optimal.
Asynchronous byzantine agreement with subquadratic communication
Published in TCC '20: Theory of Cryptography Conference, 2020
This work (co-authored with Jonathan Katz, Chen-Da Liu-Zhang, and Julian Loss) presents asynchronous Byzantine agreement (BA) protocols with expected sub-quadratic communication complexity tolerating an almost-optimal number of adaptive corruptions.
Abraxas: Throughput-efficient hybrid asynchronous consensus
Published in CCS '23: Proceedings of the 2023 ACM SIGSAC Conference on Computer and Communications Security, 2023
This paper (with Jonathan Katz, Julian Loss, Kartik Nayak, and Simon Ochsenreither) proposes Abraxas, a generic approach for constructing hybrid state-machine replication (SMR) protocols from any standard “fast path” and asynchronous “slow path.” Our design uses an “always on” slow path to improve performance when switching modes frequently.
Analyzing the real-world security of the Algorand blockchain
Published in CCS '23: Proceedings of the 2023 ACM SIGSAC Conference on Computer and Communications Security, 2023
This paper (with Derek Leung, Julian Loss, Jonathan Katz, and Tal Rabin) analyzes the Algorand blockchain protocol as it has been deployed, bridging the gap between earlier (theoretical) protocols and the deployed protocol.
Communication lower bounds for cryptographic broadcast protocols
Published in Distributed Computing, 2025
This paper (with Elette Boyle, Ran Cohen, and Chen-Da Liu-Zhang) studies the communication complexity of broadcast protocols in the dishonest-majority setting.