410 Hits in 5.4 sec

Communication Complexity of Byzantine Agreement, Revisited [article]

Ittai Abraham, T-H. Hubert Chan, Danny Dolev, Kartik Nayak, Rafael Pass, Ling Ren, Elaine Shi
2020 arXiv   pre-print
Intriguingly, they all make a common relaxation about the adaptivity of the attacker, that is, if an honest node sends a message and then gets corrupted in some round, the adversary cannot erase the message  ...  A few existing works have shown how to achieve subquadratic BA under an adaptive adversary.  ...  round complexity, and tolerates f < ( 1 2 − )n adaptive corruptions.  ... 
arXiv:1805.03391v4 fatcat:cxhb6mf5xvb3tfft2b6bytzwbm

Secure Multi-Party Computation without Agreement

Shafi Goldwasser, Yehuda Lindell
2005 Journal of Cryptology  
Furthermore, this is achieved by just replacing the broadcast channel in known protocols with a very simple and efficient echo-broadcast protocol.  ...  This is because these protocols strongly rely on the extensive use of a broadcast channel, which is in turn realized using authenticated Byzantine agreement.  ...  Acknowledgements We would like to thank Oded Goldreich for many helpful discussions, and Juan Garay for pointing out the appropriate reference to [5] .  ... 
doi:10.1007/s00145-005-0319-z fatcat:i2narlrnsjahplxte6po2wo4by

Fair Byzantine Agreements for Blockchains

Po-Chun Kuo, Hao Chung, Tzu-Wei Chao, Chen-Mou Cheng
2020 IEEE Access  
This leads to our second contribution: we propose a fair, responsive, and partition-resilient Byzantine agreement protocol able to tolerate up to 1/3 corruptions.  ...  INDEX TERMS Blockchain, Byzantine agreement, consensus, fair, responsiveness, synchronous network. This work is licensed under a Creative Commons Attribution 4.0 License.  ...  The performance and the security of such blockchain systems highly depend on the underlying Byzantine agreements, so it is imperative to design a secure and efficient Byzantine agreement protocol under  ... 
doi:10.1109/access.2020.2986824 fatcat:fam2mcdu7ndcdgsonxz7kckefq

Probabilistic Indistinguishability and the Quality of Validity in Byzantine Agreement [article]

Guy Goren, Yoram Moses, Alexander Spiegelman
2021 arXiv   pre-print
Lower bounds and impossibility results in distributed computing are both intellectually challenging and practically important.  ...  Hundreds if not thousands of proofs appear in the literature, but surprisingly, the vast majority of them apply to deterministic algorithms only.  ...  If an algorithm A solves (in a model with a strongly adaptive polynomial time adversary) Byzantine Broadcast with probability at least Proof.  ... 
arXiv:2011.04719v2 fatcat:6s5y2eitojdsrlidfamqcmxvwa

Recent Results in Scalable Multi-Party Computation [chapter]

Jared Saia, Mahdi Zamani
2015 Lecture Notes in Computer Science  
All of these algorithms rely on recent techniques from the Byzantine agreement literature on forming and using quorums. Informally, a quorum is a small set of parties, most of which are trustworthy.  ...  We describe the advantages and disadvantages of these scalable algorithms, and we propose new ideas for improving practicality of current techniques.  ...  Acknowledgments The authors would like to acknowledge supports from NSF under grants CCF-1320994, CCR-0313160, and CAREER Award 644058.  ... 
doi:10.1007/978-3-662-46078-8_3 fatcat:37fhqleqvzdarox23nnlnl3gyq

Leakage-Resilient Coin Tossing [chapter]

Elette Boyle, Shafi Goldwasser, Yael Tauman Kalai
2011 Lecture Notes in Computer Science  
We tolerate t ≤ ( 1 3 − )n computationally-unbounded Byzantine faults and in addition a Ω(1)-fraction leakage on each (honest) party's secret state.  ...  In the case of dishonest majority, it was shown to be impossible to achieve less than 1 r bias in O(r) rounds (Cleve STOC '86).  ...  Rounds 5-6: Repeat Rounds 2-3. That is, each party broadcasts a new triple of random α i ,β i ,γ i and then broadcasts the linear combinationṽ i =αs i +βr i +γr i of his shares. 6.  ... 
doi:10.1007/978-3-642-24100-0_16 fatcat:tbdyurs2gbbsjcvqd6wcrsnoqy

Leakage-resilient coin tossing

Elette Boyle, Shafi Goldwasser, Yael Tauman Kalai
2014 Distributed computing  
In the case of dishonest majority, it was shown to be impossible to achieve less than 1 r bias in O(r) rounds (Cleve STOC '86).  ...  We tolerate t ≤ ( 1 3 − )n computationally-unbounded Byzantine faults and in addition a Ω(1)-fraction leakage on each (honest) party's secret state.  ...  Rounds 5-6: Repeat Rounds 2-3. That is, each party broadcasts a new triple of random α i ,β i ,γ i and then broadcasts the linear combinationṽ i =αs i +βr i +γr i of his shares. 6.  ... 
doi:10.1007/s00446-013-0206-z fatcat:tgcwsevzfrdvtgqtgitamlhwku

Payment Does Not Imply Consensus (For Distributed Payment Systems) [article]

Thomas Orton
2021 arXiv   pre-print
In Theorem 1, we show that even though there exists a single step black box reduction from Payment Systems to Byzantine Broadcast, there does not exist any black box reduction in the other direction which  ...  In this paper, we formally define a model of payment systems, and present two main results.  ...  For any f ∈ N such that 3f < N , Byzantine Broadcast is not strongly reducible to the Marker Problem in fewer than f +1 3 simulation steps.  ... 
arXiv:2105.11821v1 fatcat:fdx2cme5bfezfexa37s6j66gc4

Holdout SGD: Byzantine Tolerant Federated Learning [article]

Shahar Azulay, Lior Raz, Amir Globerson, Tomer Koren, Yehuda Afek
2020 arXiv   pre-print
Empirical evaluation shows that HoldOut SGD is Byzantine-resilient and efficiently converges to an effectual model for deep-learning tasks, as long as the total number of participating workers is large  ...  and the fraction of Byzantine workers is less than half (<1/3 for the fully distributed variant).  ...  under a Byzantine fraction f < 0.5.  ... 
arXiv:2008.04612v1 fatcat:kxkapnl2draxbmhyfgbm2zhjpm

On the Round Complexity of Randomized Byzantine Agreement [article]

Ran Cohen and Iftach Haitner and Nikolaos Makriyannis and Matan Orland and Alex Samorodnitsky
2019 arXiv   pre-print
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.  ...  ., n/4] corruptions terminate (under attack) at the end of the first round with probability at most o(1) [resp., 1/2+ o(1)]. (2) BA protocols resilient against n/4 corruptions terminate at the end of the  ...  We would like to thank Rotem Oshman, Juan Garay, Ehud Friedgut, and Elchanan Mossel for very helpful discussions.  ... 
arXiv:1907.11329v3 fatcat:txeiyvv5bjbh7pzwlmxqak5yge

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

Iftach Haitner, Yonatan Karidi-Heller
2020 arXiv   pre-print
In this work we close the above gap, proving that no n-party protocol (of any round complexity) is resilient to ω(√(n)) (adaptive) corruptions.  ...  In an adaptively secure full-information coin flip, Ben-Or and Linial [FOCS '85], the parties communicate over a broadcast channel and a computationally unbounded adversary can choose which parties to  ...  Acknowledgment We are grateful to Raz Landau, Nikolaos Makriyannis, Eran Omri and Eliad Tsfadia for very helpful discussions.  ... 
arXiv:2005.01565v2 fatcat:tx5d4lcvrncvdg5wfsudw2yfwi

LinSBFT: Linear-Communication One-Step BFT Protocol for Public Blockchains [article]

Xiaodong Qi and Yin Yang and Zhao Zhang and Cheqing Jin and Aoying Zhou
2020 arXiv   pre-print
Further, in the ordinary case, LinSBFT involves only a single round of voting instead of two in PBFT, which reduces both communication overhead and confirmation time, and employs the proof-of-stake scheme  ...  This paper presents LinSBFT, a Byzantine Fault Tolerance (BFT) protocol with the capacity of processing over 2000 smart contract transactions per second in production.  ...  Algorand [14] addresses the situation where the adversary is adaptive, who can instantly corrupt any node at will. As pointed out by Chan et al.  ... 
arXiv:2007.07642v1 fatcat:qrxrbda5jnagdho72nj43qhlsq

Distributed Statistical Machine Learning in Adversarial Settings: Byzantine Gradient Descent [article]

Yudong Chen, Lili Su, Jiaming Xu
2017 arXiv   pre-print
We show that our method can tolerate q < (m-1)/2 Byzantine failures, and the parameter estimate converges in O( N) rounds with an estimation error of √(d(2q+1)/N), hence approaching the optimal error rate  ...  A key challenge arises in the above problem is that Byzantine failures create arbitrary and unspecified dependency among the iterations and the aggregated gradients.  ...  When the population risk F is strongly convex, BGD converges exponentially fast, and hence requires only a few rounds of communication.  ... 
arXiv:1705.05491v2 fatcat:2auowhscqzgwnmpvddrralx6vm

A Survey on Fault-tolerance in Distributed Optimization and Machine Learning [article]

Shuo Liu
2021 arXiv   pre-print
theories and applicable algorithms.  ...  The robustness of distributed optimization is an emerging field of study, motivated by various applications of distributed optimization including distributed machine learning, distributed sensing, and  ...  Peer-to-peer network The majority of Byzantine fault-tolerant algorithms are built under the server-based architecture, e.g., [6, 18, 49] , etc.; while studies under peer-to-peer architectures, although  ... 
arXiv:2106.08545v2 fatcat:g6fys4icrbbr5k3bd3ycylaptu

Network-Hiding Communication and Applications to Multi-party Protocols [chapter]

Martin Hirt, Ueli Maurer, Daniel Tschudi, Vassilis Zikas
2016 Lecture Notes in Computer Science  
tolerates any adversary who passively corrupts arbitrarily many network nodes.  ...  ., polynomial with small constants-communication and computation overhead. We further show how to construct anonymous broadcast without using expensive MPCs to setup the original pseudonyms.  ...  a variant of anonymous broadcast where parties can broadcast messages under a pseudonym.  ... 
doi:10.1007/978-3-662-53008-5_12 fatcat:kbox7z42wvfohbzgl5sxiqprji
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